# Shimano R785 disc levers have excessive free stroke



## warx (Aug 29, 2012)

Hi,

I've bled these things several times with all the tricks (removing so hose is dead vertical, flicking hose, tilting etc.) but I realized my problem is the free stroke at the caliper is too much. Looks like they back off from the pads a lot so much of the stroke is just closing the gap. The free stroke adjustment is all the way in (least free stroke) but the lever still moves 25mm before pads engage so I have to leave the reach at maximum to ensure they don't bottom out. I read the road.cc review which mentions this. I just don't see a way I can do anything about it except mount the hoods on my drop bars where they have the most room to pull in. Crazy. 

I can actually get enough braking force out of them but as also mentioned if doing a cross race and braking into barriers you trap your non braking fingers under the lever every time. Might try the stiffer BH90 hose to at least make the lever firmer once the pads have moved in to the disc and reduce travel that way.


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## cxwrench (Nov 9, 2004)

Sounds to me like you're not bleeding them correctly. I've installed them on lots of bikes and have had no problems like this.


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## warx (Aug 29, 2012)

That's what I thought but the pads start moving immediately the levers move. It just takes a lot of travel to move the pads in. Once they're touching the disc they are pretty firm just a half of the lever movement is already used up. There's like 1mm of clearance of pad and disc which seems a lot to me. If they just stopped backing off the disc so much they would be great.


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## ghettocop (Apr 19, 2014)

After you do a complete, thorough, and correct bleed, pump the lever a few times with the system closed. Then (keeping the lever end closed) open the bleed valve at the caliper and force some more fluid into the caliper. Don't push the syringe as hard as you can or anything, but push hard enough that you can see and feel a small amount of fluid enter the caliper. Close valve and check lever pull now. I have done this a few times on various shimano systems to get a really "high and hard" lever. Seems to work.


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## warx (Aug 29, 2012)

OK. Thanks. Will try that. I bleed as the manual instructs and did the final hold lever and open bleed port for half-second to squirt some liquid back into the syringe. Did this twice as I noticed if you do it more then it starts to get worse even though there's no re-introduction of air anywhere. 

I guess what you're doing with one-last syringe plunge is sort of pre-loading the pressure a bit and perhaps closing the pads in. Do you find you have to repeat this once the pads wear a bit? I don't really know how the reservoir works on these levers and when is shuts it off and starts pressurizing but felt like that was too far into the lever travel.


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## nhluhr (Sep 9, 2010)

If you're following the correct procedure ( http://si.shimano.com/php/download.php?file=pdf/dm/DM-BR0004-02-ENG.pdf ) it sounds to me like maybe you're either missing steps like forgetting to turn the freestroke/reach adjustment screws to the correct position before bleeding or maybe you're forgetting to use the red pad spacer to properly space the pistons before installing the wheel.


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## Special Eyes (Feb 2, 2011)

I have a similar situation that I live with successfully. After adjusting the free stroke on the lever itself, there is still too much movement before the brakes kick in. The stroke adjustment on the lever if fairly useless, it is so small. I set the brakes up new on a new build and bled and checked. No air bubbles were ever introduced. I don't believe there are any other adjustments or methods to reduce the 2" of useless stroke of the lever before the brakes apply.

What red pad spacer are you talking about? None included or shown in the documentation. Also, I don't believe shimming the pad will lessen the free stroke.


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## nhluhr (Sep 9, 2010)

Special Eyes said:


> What red pad spacer are you talking about? None included or shown in the documentation.


Shimano hydraulic calipers come with the red pad spacer to ensure proper gapping for the standard 1.8mm rotor. In fact, all hydraulic brakes come with a spacer of some kind but Shimano's is red. This goes along with the yellow bleed block that you also use (if doing the job correctly).

http://youtu.be/9JrDwRuu8Gw?t=36s


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## cxwrench (Nov 9, 2004)

nhluhr said:


> Shimano hydraulic calipers come with the red pad spacer to ensure proper gapping for the standard 1.8mm rotor. In fact, all hydraulic brakes come with a spacer of some kind but Shimano's is red. This goes along with the yellow bleed block that you also use (if doing the job correctly).
> 
> http://youtu.be/9JrDwRuu8Gw?t=36s


^This^ Hopefully you're not bleeding them w/ the rotor and pads in place. Bleed them w/ the yellow bleed block, then install the pads. Then use the red pad spacer to set the pistons. And follow all the other instructions in the linked Shimano doc provided.


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## warx (Aug 29, 2012)

Interesting. I understood the red spacer was used solely for checking the piston movement. It is only mentioned in the notes when there's no wheel/disc and you don't want the brakes applied accidentally and the sections "Adjustment when the pistons are not operating correctly" and "Replacing pads" under maintenance. They should really mention this in the "Installation" part.

I will use it to set the gap. I presume the spacer is thinner than the disc standard. A question I would ask is that do the pads stay gapped correctly as they wear if they need to be gapped by something thinner than a disc itself? Or must you regularly pop the red spacer in there to set it tighter again?

I ran into a Roubaix SL4 disc at Pantoll Station (Mt Tam, Norcal) today. Nice deep Roval carbon wheels, freeza centerlock rotors. I asked to feel his brakes (whoa!). He obliged and let me try and as I was he said "sometimes I pinch my fingers under the lever." This was a bike built by Specialized. Maybe this is a communication thing...


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## cxwrench (Nov 9, 2004)

warx said:


> Interesting. I understood the red spacer was used solely for checking the piston movement. It is only mentioned in the notes when there's no wheel/disc and you don't want the brakes applied accidentally and the sections "Adjustment when the pistons are not operating correctly" and "Replacing pads" under maintenance. They should really mention this in the "Installation" part.
> 
> I will use it to set the gap. I presume the spacer is thinner than the disc standard. A question I would ask is that do the pads stay gapped correctly as they wear if they need to be gapped by something thinner than a disc itself? Or must you regularly pop the red spacer in there to set it tighter again?
> 
> I ran into a Roubaix SL4 disc at Pantoll Station (Mt Tam, Norcal) today. Nice deep Roval carbon wheels, freeza centerlock rotors. I asked to feel his brakes (whoa!). He obliged and let me try and as I was he said "sometimes I pinch my fingers under the lever." This was a bike built by Specialized. Maybe this is a communication thing...


Built by Specialized or since you're in the middle of Mike's Bikes territory, built by them? Must have been nice up on Tam today, it's been a perfect day in Marin.


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## warx (Aug 29, 2012)

Rode from GGB, Headlands, Ten. Valley, Coastal, Deer Park, Pantoll, Coast View, Middle Green Gulch, Miwok, Headlands. Gotta love this place!

True about the stores - I guess a delivering bike store could be responsible. I am never sure if a bike arrives at a dealers with just the handlebars and wheels removed or separate parts. If so it is more likely a communications thing. Shimano needs to communicate to its dealer/assemblers better. Their docs leave a lot to be desired.


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## nhluhr (Sep 9, 2010)

Shimano's docs are light years ahead of SRAM's cryptic pictographic flyers. I do find it odd the dealer manual doesn't mention the red spacer in the bleed instructions but on shimano' online tech videos they offer dealers, the red pad spacer is mentioned in every single video dealing with hydraulic braked to the point where it's drilled into your head.


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## cxwrench (Nov 9, 2004)

warx said:


> Rode from GGB, Headlands, Ten. Valley, Coastal, Deer Park, Pantoll, Coast View, Middle Green Gulch, Miwok, Headlands. Gotta love this place!
> 
> True about the stores - I guess a delivering bike store could be responsible. I am never sure if a bike arrives at a dealers with just the handlebars and wheels removed or separate parts. If so it is more likely a communications thing. Shimano needs to communicate to its dealer/assemblers better. Their docs leave a lot to be desired.


Jesus...you got all of it today. I, OTOH, went to lunch at Pacific Catch w/ mom and picked up a rental car. Also hit TJ's for some essential frozen treats. I am building a bike for a girl on Velocio today, but didn't get close to riding one. 

The s-tec website that dealers have access to is very thorough as nhluhr posted. They really beat us to death w/ the red pad spacer stuff. But I wouldn't expect the majority of Specialized shops in Marin to even know about s-tec, much less actually log in and pay attention to the videos.


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## Special Eyes (Feb 2, 2011)

OK I saw the red bleed block in that Art's Cyclery video. I built up a Vamoots DR recently with 2014 R785 disc brakes and Di2. There was a YELLOW bleed block in the brand new kit. Apparently they are the same. I was misled by mention of a red piston spacer.


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## cxwrench (Nov 9, 2004)

Special Eyes said:


> OK I saw the red bleed block in that Art's Cyclery video. I built up a Vamoots DR recently with 2014 R785 disc brakes and Di2. There was a YELLOW bleed block in the brand new kit. *Apparently they are the same.* I was misled by mention of a red piston spacer.


Nope. The yellow 'bleed block' is what you use when bleeding the brakes. It fills up the space between the pistons when the pads are removed. The red 'pad spacer' is what is used to set the pistons in the right place when you're done bleeding and the pads are installed. Not the same piece.


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## nhluhr (Sep 9, 2010)

Special Eyes said:


> OK I saw the red bleed block in that Art's Cyclery video. I built up a Vamoots DR recently with 2014 R785 disc brakes and Di2. There was a YELLOW bleed block in the brand new kit. Apparently they are the same. I was misled by mention of a red piston spacer.


The video link I posted puts you in the exact part of the video where the guys says they are two different tools.


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## Special Eyes (Feb 2, 2011)

nhluhr said:


> I do find it odd the dealer manual doesn't mention the red spacer in the bleed instructions but on shimano' online tech videos they offer dealers, the red pad spacer is mentioned in every single video dealing with hydraulic braked to the point where it's drilled into your head.


I guess that was the experience I was referring to, except for the video parts. It simply wasn't shown in the docs. I did not watch any videos, and nothing indicated that I had to find them independently. I thought the slim spacer was to be put in between the pads when the wheel was removed for transport in case the brake lever was pressed with no rotor in there. Made sense to me.


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## cxwrench (Nov 9, 2004)

Special Eyes said:


> I guess that was the experience I was referring to, except for the video parts. It simply wasn't shown in the docs. I did not watch any videos, and nothing indicated that I had to find them independently. I thought the slim spacer was to be put in between the pads when the wheel was removed for transport in case the brake lever was pressed with no rotor in there. Made sense to me.


That's what everyone thinks they're for, hell...that's what I thought they were for til a couple years ago. They come in new brakes, they come w/ new bikes...makes sense they'd be used as a 'travel spacer'. We just had the wrong meaning for 'travel'.


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## Special Eyes (Feb 2, 2011)

cxwrench said:


> We just had the wrong meaning for 'travel'.


Good point, CX!


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## warx (Aug 29, 2012)

I worked on my brakes a bit last night. It's funny as when the yellow bleed block in in the calipers the levers feel solid - mainly as the block is thicker than the pads and red spacer. I know the lever is functioning correctly and there's no air in the line. 

Using the red spacer and a few hard squeezes does set the pads marginally closer to the disc and reduced the free-stroke a bit. Enough to where I could not squeeze the lever so tight I could bottom out (given the reach is set to max and free-stroke adjustment is min)

The one issue that remains is specific to cyclocross is that the front brake lever will still pinch any fingers left around the bar when braking hard into a dismount. But looking at this I realize those paddle buttons are pretty darn big! I am coming from TRP Hylex (single-speed) hydraulics where there's no gear shifter on the levers so plenty of room under. I think I just need to adjust my technique. Also I am going to be using a 1x11 (XTR) so could remove the left/front shifter switches anyways.

One final test is I made a spacer thinner than the red spacer and set the pads with that and it gave me a perfect tighter clearance gap and super-solid lever feel. I could even wind the reach in a little bit. I'll try with this and see how it fairs as the pads wear.

I did get some BH90 hoses (much stiffer and less compressible) and might still try this for the rear. I am more used to hydraulic discs than rim cables so don't need a particular feel to them.


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## bedwards1000 (May 31, 2002)

warx, did you finally get this the way you like it? I just took delivery of a lightly used bike with R785s and have the same problem. The brakes engage just before the bars but otherwise work fine. I've done zero tinkering yet but was reading up on it to see what worked.


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## warx (Aug 29, 2012)

Not quite the way I'd like it TBH. I do the trick with the shim to set them closer than just setting them on the disc and it's better - but still seams like too much travel. I guess I am used it now. I still might try using an even thinner shim to set them closer.

Now cross season is almost here I am practicing dismounts and this is where it feels the most wrong. I was used to having fingers under the lever during a dismount. I can't do that now. I suppose it was a bad habit.


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## bedwards1000 (May 31, 2002)

Thanks for the quick reply. I haven't done or noticed it on the dismounts (only had the bike 2 rides) but on sketchy downhill stuff I hang onto the hoods with a finger wrapped around and the travel is too much. I haven't even played with the stroke adjustment. I've had the bike <24 hours and I've been riding it 5 or those and sleeping the rest.  Now I'm at work so I can do some research.


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## J.R. (Sep 14, 2009)

Just use a shim to move the pads closer together. By using a thinner shim you can move the pads as close as you want which results in a "high and hard" brake lever.


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## bedwards1000 (May 31, 2002)

Thanks, I'm glad I asked, I'll be way closer to getting it right than if I started tinkering blind. 

Somebody suggested using playing cards as shims since you can get any thickness to get any lever feel you want. 

I know enough to be dangerous!


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## J.R. (Sep 14, 2009)

I thought it was pretty easy. Pull the wheel, insert spacer, pump brake lever until pads are against spacer, put the wheel back on and ride.

Playing cards should work. You may need to experiment a bit to get the right amount.

I just used a piece of brass stock I had handy.


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## wgscott (Jul 14, 2013)

One thing I discovered the hard way is you don't want to do a bleed with worn pads in place. You need fresh pads, or a spacer to match, or there won't be enough expansion room when you go to replace your warn pads.

Conversely, I have noticed that the travel increases quite noticeably when the pads need to be replaced (you need to do so before they become as thin as the spring metal that hold them apart).


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## warx (Aug 29, 2012)

Yeah - it's about getting the right thickness shim for your desired gap. I still think the stock gap setting it either on the rotors themselves or the shim (which pretty much measures almost the same as the rotor) is too wide. Never had disc brakes that separated before.


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## bedwards1000 (May 31, 2002)

Unfortunately, I don't think I got the spacer in the box of goodies that came with the bike. Does anybody have a pair of calipers to measure the thickness? I think I'm on the right track.


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## warx (Aug 29, 2012)

As I suspected, my orange/red spacers measure 1.82mm which is thicker than all my various rotors (1.71-1.74mm). So whatever gap I set with them is overridden by the first application on the rotor itself. I have been using some 0.040 (1mm) aluminum sheet instead although I might try some 0.025 sheet.


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## wgscott (Jul 14, 2013)

bedwards1000 said:


> Unfortunately, I don't think I got the spacer in the box of goodies that came with the bike. Does anybody have a pair of calipers to measure the thickness? I think I'm on the right track.


I didn't either. I had to wing it. The deck of cards idea sounds ideal. Then count the cards you need to get it right and save that info for the next time you have to bleed your brakes, so that [sarc]six weeks from now when you have to do it again[/sarc], you won't have to do all the experimenting again.


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## cxwrench (Nov 9, 2004)

wgscott said:


> One thing I discovered the hard way is you don't want to do a bleed with worn pads in place. You need fresh pads, or a spacer to match, or there won't be enough expansion room when you go to replace your warn pads.
> 
> Conversely, I have noticed that the travel increases quite noticeably when the pads need to be replaced (you need to do so before they become as thin as the spring metal that hold them apart).


You _don't ever want to bleed a brake w/ the pads in_. Too easy to ruin your pads.


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## wgscott (Jul 14, 2013)

I was thinking more in terms of the final adjustment just before you take the upper syringe off.


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## jamesgumby (Mar 28, 2007)

Quick question. I have new 785s and the same issue. It isn't too much 'freestroke' as the pads move with the lever from the word go. 

So.... when bleeding with yellow block, do I back off the freestroke screw first? (It comes set to minimum, ie. screwed right in) and then screw it in after completing all procedures...or will this make no difference?

Cheers


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## Srode (Aug 19, 2012)

Just got done installing a set on my new build and the front has very little travel before biting, feels nice and solid. The rear travels a long way, but still stops well. I read the thread, not sure I want to play with shims - shouldn't have to. Maybe I'll get another bottle of fluid and try again.


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## rcb78 (Jun 15, 2008)

I just did a set of 685s that came completely dry, new lines, disconnected, etc. I tried it the Shimano way and it felt pretty good. Then I tried hooking up syringes to both sides and bleeding like I do my Avid brakes and 'vacuumed' out a few more bubbles giving a slightly better lever feel that was balanced left to right.
Having tried it both ways now, I think I'll stick to the dual syringe method. Seemed faster and more effective.
FWIW, the syringes I use are from the Jagwire universal kit for mineral oil. Very similar to the pro level Avid kit except the syringes aren't rebuildable.


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## wgscott (Jul 14, 2013)

I don't know if this is an acceptable protocol, but I used the top syringe to generate negative pressure to suck out as much air as possible. I found in order for this to work, I had to put a thin layer of high vacuum grease in the Luer lock thread to keep it from leaking under negative pressure. Having said that, I have never gotten the back brake as nice and solid as the front. They guy who built my bike did, so I know it is possible.


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## Lelandjt (Sep 11, 2008)

In the MTB world Shimano brakes are known for having lots of rotor clearance which is great for accomodating wobbly rotors. They also have a long free stroke. Some people overfill them to reduce this. How long it takes to go from the overfilled state to normal seems to vary from days to months.


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## jamesgumby (Mar 28, 2007)

Ok, finally done my brakes. Bled according to Shimano instructions. Then closed all oil ports, attached syringe to caliper, undid caliper port and pumped in a bit more (with yellow block in).

Then....reset pistons with wheel in, by lightly pulling lever. Didn't use red spacer. Levers really firm now.


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## Srode (Aug 19, 2012)

The mechanic at a shop I use went to Shimano school on the brakes and was told that the instructor was asked at races to do the extra shot in the caliper after bleeding to bring the freestroke to something the rider liked which he did. The instructor said he didn't recommend it for recreational riders because it's hard on equipment. Pros have plenty of money to spend on parts of course and an ample supply. What wasn't relayed to me was what specifically it's hard on, but I would guess heat expanding the fluid might put extra pressure on parts might be a problem - although there's plenty of pressure on parts when the brakes are applied too so that may not make sense either.


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## Srode (Aug 19, 2012)

J.R. said:


> Just use a shim to move the pads closer together. By using a thinner shim you can move the pads as close as you want which results in a "high and hard" brake lever.


After trying bleeding twice and still ending up with too much freestroke on the rear, I tried the shim method using a feeler gauge set with about a 1.4mm stack and it feels much better, thanks for the tip! I figured the feeler gauge approach would be easy to dial in and reproduce once I found a thickness that works with new rotors. Worn ones will probably need a thinner stack obviously. 

Before the feeler gauge I used the red spacer and saw little if any improvement - Using a caliper to measure the rotor and the red spacer they were both at around 2mm so it's easy to see why it didn't help any.


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## tlg (May 11, 2011)

I made some custom 3D printed bleed blocks if anyone is interested. They work better than shimming. I've made sizes 1mm & 0.5mm thinner than the standard Shimano block. If you want other thickness, let me know. I can make them any size you want.

Bleed Block-1mm (NN5BKSGNJ) by tlgpa
Bleed Block-.5mm (A9DAXVXWP) by tlgpa


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## Srode (Aug 19, 2012)

tlg said:


> I made some custom 3D printed bleed blocks if anyone is interested. They work better than shimming. I've made sizes 1mm & 0.5mm thinner than the standard Shimano block. If you want other thickness, let me know. I can make them any size you want.
> 
> Bleed Block-1mm (NN5BKSGNJ) by tlgpa
> Bleed Block-.5mm (A9DAXVXWP) by tlgpa


How cool, great application of 3D printing!


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## gooded (Apr 28, 2016)

I just "fixed" my RS685 (Ultegra) using the feeler gauge approach. My rotor measures 0.070". I used 0.045 "shims" (0.014+0.015+0.016 feeler gauges at the same time). Free stroke is DIALED now. I went from thinking disc brakes were "meh", to thinking they're rad. Thank you for the ideas.


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## looigi (Nov 24, 2010)

warx said:


> I worked on my brakes a bit last night. It's funny as when the yellow bleed block in in the calipers the levers feel solid - mainly as the block is thicker than the pads and red spacer. ...


Not funny, but normal and expected. The pistons are retracted by their seals. For the seals to retract, the piston must move out enough to exceed the elastic travel of the seals and preload them in the inward direction. This is the so called "resetting the pistons". when pushing the pistons all the way in, the seal is preloaded in the outward direction pushing the piston against the bleed block. As such, there is no piston retraction from the block and this is responsible for the reduction in free travel.


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