[nemesis256]

I'm just installing these brakes on my bike, and they're feeling spongy. The lever also has to move a lot before the pads engage the rotors. I've bled the rear brake because it was the worst, with maybe negligible improvements. I've pushed about 20 ml of fluid twice through the rear brake (how much is in there anyway?) and only saw bubbles when first starting out. A ton of fluid came out of the caliper when I removed the bleed screw from it as well. The second time I pushed more fluid in there were maybe very tiny bubbles in the syringe.

I've bled SRAM brakes before but this is my first time with mineral oil. SRAM has about 30 more steps but the syringes are much higher quality and the process of pulling on it to create a vacuum and get more air out gives me more confidence in being successful.

I'm using a single syringe and a screw in cup on the lever with these TRP brakes. I have pumped the lever multiple times and held the lever down for 15 mins or so multiple times while the bleed port on the lever was open with the cup containing fluid.

What am I doing wrong?

 

[MTBMILES]

Did you watch the trp bleeding video?


Sent from my iPhone using Tapatalk

 

[nemesis256]

yes I did.

I just tried the trick of holding down the brake lever with mineral oil in the cup overnight. At first it felt better, but literally 10 minutes after closing the bleed port it's crap again.

 

[Cotharyus]

Your description makes it sound like the biggest problem is lever free stroke before the pads make contact. Is that the case, or once they make contact is the lever still mushy?

 

[nemesis256]

Your description makes it sound like the biggest problem is lever free stroke before the pads make contact. Is that the case, or once they make contact is the lever still mushy?

A little bit of both, but primarily the free stroke.

Oh, and through out this entire overnight process, I haven't seen any air bubbles come up. Only time I've seen air bubbles is the first time I pushed oil from the caliper.

 

[LyNx]

Did you check that everything is tightened down properly and no air is getting into the system? Sounds a bit like you've got a leak, as on most any brake, you might get a drop of fluid escaping the bleed port screw when you undo it with the rest of the system closed, but lots shouldn't come out. You did undo the bleed screw with the rest of the system closed off, right? Go search YouTube for the video John Hall did on bleeding them, think it was when they were still with YT.

 

[nemesis256]

Did you check that everything is tightened down properly and no air is getting into the system? Sounds a bit like you've got a leak, as on most any brake, you might get a drop of fluid escaping the bleed port screw when you undo it with the rest of the system closed, but lots shouldn't come out. You did undo the bleed screw with the rest of the system closed off, right? Go search YouTube for the video John Hall did on bleeding them, think it was when they were still with YT.

When doing the mini bleed from the lever, yes everything else was closed, and not a lot comes out from the lever. It's from the caliper when I was doing the real bleed that a lot came out. Can't remember if the lever port was open at that time. They obviously have to be both open to bleed, so which should be open first?

 

[127.0.0.1]

if you can get a syringe to fit the lever bleed hole, do minibleeds/lever grabs and suck those bubbles out and press fluid in...need to be able to apply vacuum and pressure at lever w/o leaks at syringe

*my magura's needed two minibleeds after a full bleed (on front only , go figure) and after two minibleeds they are perfect now. I'm not overthinking how a proper full bleed on both resulted in a back brake not needing a minibleed and a front brake needing two, but bubbles were hidden and minibleeds took care of it.

 

[nemesis256]

if you can get a syringe to fit the lever bleed hole, do minibleeds/lever grabs and suck those bubbles out and press fluid in...need to be able to apply vacuum and pressure at lever w/o leaks at syringe

I just tried this, at first I was hopeful. I got a bunch of air out and when pushing down on the syringe they felt great. But then I remove the syringe and A TON of fluid leaks out, losing all the pressure. I close it as quickly as I can, negligible improvement in the brakes.

I'm really getting tired of this!

 

[127.0.0.1]

I just tried this, at first I was hopeful. I got a bunch of air out and when pushing down on the syringe they felt great. But then I remove the syringe and A TON of fluid leaks out, losing all the pressure. I close it as quickly as I can, negligible improvement in the brakes.

I'm really getting tired of this!

the idea is after a few cycles (5-10 times, slow) you don't actually want pressure, you want about neutral when done...only a tiny amount to leak out, just enough to keep air out while closing off port

 

[Redlands R&C]

Do the TRP's have the same fitting/threading so that you can use the shimano "cup" to put on top of the lever?

**Edit, looks like TRP has its own similar bleed funnel, but the idea is the same. --
My reason for asking is, the BEST shimano brake bleed I ever did I let sit overnight. I was trying to finish the bleed, then had to go take care of family business upstairs. So I left a half full cup on the lever, but closed off the caliper end of it. Had the funnel at the top, and the caliper was hanging low and probably wiggled a bit overnight. I think the time allowed the bubbles to rise to the top on their own, rather than the tricks to try to get all the bubbles out. Those felt the best, and between my own projects and the shops I've worked at, I've rarely been able to duplicate it, at least in a "quick" fashion.

 

[ocnLogan]

I've got a pair of Quadiems, and they were the literal first brakes I've ever bled in my life, and even I (a complete newbie) didn't have any issues. So I'm wondering if the bleed isn't actually the problem.

You said they feel spongey, but mostly that the issue is free stroke. Then I also see that you said that the pads are super far away from the rotors.

Perhaps the issue is just that the pistons just need to come out of the caliper a bit? A trick some people use to reduce free stroke is to take the wheel off, and pull the lever a bit, and the pistons will start to close the gap to the rotor. Be careful though, as you wouldn't want a piston to come out (or the pads to be too close to slot the rotor in between).

Alternatively, are maybe your rotors worn/really thin? that could cause the same behavior as above.

Also, you did mention that using the bleed cup overnight made things feel fine for a while. That does sound kind of like it could be a leak, as once bled, the brakes shouldn't really change their feel once closed up (and, especially, not ridden/or moved positions). My pair has felt the same since the bleed, and I've got ~4500ft of descending on them since the install.

Did you trim the hoses to length when you got the brakes (and if you did, was it at the caliper end of the lever end)? Also, are you sure the hoses got tightened correctly? What about the barbs/olives?

If all else fails, I'd reach out to TRP, and/or the reseller where you purchased them. At least based on my experience, somethings sounds wrong, and I'd give them the chance to make it right before doing much else.

Good luck getting it sorted out. I really do think you'll like them once you get them working correctly, its just a bummer you haven't had as smooth of sailing as I had on my pair .

 

[LyNx]

Exactly why I said check for a leak, strange for them to feel good, then not, something isn't right with the system.

I've got a pair of Quadiems, and they were the literal first brakes I've ever bled in my life, and even I (a complete newbie) didn't have any issues. So I'm wondering if the bleed isn't actually the problem...........................

Also, you did mention that using the bleed cup overnight made things feel fine for a while. That does sound kind of like it could be a leak, as once bled, the brakes shouldn't really change their feel once closed up (and, especially, not ridden/or moved positions). My pair has felt the same since the bleed, and I've got ~4500ft of descending on them since the install.

Did you trim the hoses to length when you got the brakes (and if you did, was it at the caliper end of the lever end)? Also, are you sure the hoses got tightened correctly? What about the barbs/olives?

If all else fails, I'd reach out to TRP, and/or the reseller where you purchased them. At least based on my experience, somethings sounds wrong, and I'd give them the chance to make it right before doing much else.

Good luck getting it sorted out. I really do think you'll like them once you get them working correctly, its just a bummer you haven't had as smooth of sailing as I had on my pair .

 

[nemesis256]

Did you trim the hoses to length when you got the brakes (and if you did, was it at the caliper end of the lever end)? Also, are you sure the hoses got tightened correctly? What about the barbs/olives?

I did trim them myself, on the lever end. I've been wondering about the olives as well. When I remove the screw cover where the olive is by the lever, there's a tiny amount of oil when I wipe it with my finger. But I mean really tiny. Not enough to make a drop, just enough to say my finger is barely wet. I did use a torque wrench on those, and they felt pretty darn tight.

 

[nemesis256]

Another update. I just pulled on the lever with nothing in between the pistons to try to set their start position closer to the disc. Some progress maybe, leaving the cup with oil in for a while before I can test for real. But while doing that I noticed the calipers don't all move at the same rate. There's one especially that barely budges. This is on the front brake, haven't looked at the rear yet. Is it something to be concerned about? Is it part of the problem?

 

[ocnLogan]

I did trim them myself, on the lever end. I've been wondering about the olives as well. When I remove the screw cover where the olive is by the lever, there's a tiny amount of oil when I wipe it with my finger. But I mean really tiny. Not enough to make a drop, just enough to say my finger is barely wet. I did use a torque wrench on those, and they felt pretty darn tight.

I'd be worried about that. Any oil there sounds wrong to me.

Have you tried wiping it clean/crazy dry, and then cycling the brakes with the wheel on for a bit (aka, pressurizing the system)? If there is a leak in the hose, or the olive, that should trigger it. And if you see oil in that area again, then thats likely your problem.

I can check mine when I get home tonight, but I don't think there is any oil there on mine.

Another update. I just pulled on the lever with nothing in between the pistons to try to set their start position closer to the disc. Some progress maybe, leaving the cup with oil in for a while before I can test for real. But while doing that I noticed the calipers don't all move at the same rate. There's one especially that barely budges. This is on the front brake, haven't looked at the rear yet. Is it something to be concerned about? Is it part of the problem?

These are my first 4 piston brakes. But, from what I understand/have read, this is relatively normal (to have a "sticky" piston or two). Try looking up "resetting pistons", and see if you can coax that piston to move normally.

 

[Lone Rager]

It's normal. Which ever pistons advances first is the one that will advance. There's no mechanism that keeps them the same. You need to hold that piston to force the other to advance.

Free stroke, bite point, and a soft lever are three separate things and need to be separately addressed. The lever needs to firm and the bite point correct. Some free stroke is essential to braking function. There has to be enough to allow the caliper pistons to retract and the lever piston to retract behind the reservoir transfer port. Some brakes include a free stroke adjustment which can reduce it to a degree by moving the lever piston closer to the reservoir port.

If you remove the rotor and pre-set the pistons closer together to reduce clearance between the pads and rotor, you will reduce free stroke but the pads will almost certainly rub. As they wear, the free stroke will increase, but worse, the bite point will move closer to the grip which can reduce your ability to brake effectively.

 

[nemesis256]

I don't think what I did with leaving the pistons out a bit did much. From what I can see and feel they're back in their original position.

I'm getting close to opening the reservoir in the lever to see how much fluid is in there. Getting desperate. I'll probably try bleeding from the lever again like 127.0.0.1 mentioned and try to not pressurize but just fill, before I try the reservoir.

 

[nemesis256]

Good news and bad news. Good news is that I finally firmed up the lever by leaving the pistons out a little more. Bad news is that in the process of putting the bike together, I did a very stupid thing and forgot the put the pads back on. One of the pistons popped out. Luckily it didn't fall to the ground and I was able to put it back in. Wiped everything real good after that.

So of course I had to rebleed everything since half the oil came out. In the end I've got it firm again, but maybe a little to much, because the pads always rub on the rotor. So I might have a squealing problem.

Any problems here with the one piston popping out and going back in?

 

[ocnLogan]

So it sounds like the problem wasn't the bleed then, it was just the pads being too far away from the rotor.

Have you measured your rotor thickness? I've not had it happen to me, but I hear that especially metalic pads can wear down rotors, and there is actually a minimum thickess listed for most brands. Its just interesting that you had so much free stroke, where I didn't have any issues with mine. So either you're more sensitive to lever travel before brake engagement than I am, its that my rotors are new, so the pads are closer to them.

And, AFAIK there isn't any issues with having pistons pop out, other than the mess/etc. As long as it was cleaned up well, and the seals were in good shape, then you should be good to go.

And if your pads are always in contact with the rotors, then you simply need to take the pads out again, and push in on them a bit to get them to retract a bit (just like when you replace brake pads, the pistons are over-extended). Eventually you'll find the middle ground, and it sounds like you'll be happy .