SRAM brakes jamming...
 

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SRAM brakes jamming on

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 rone
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I'm a hope man but a couple of bikes had SRAM rival on that i bought - and intended to swap at some point. But I left them due to finances and thinking they can't be that bad.

But both different bikes - with SRAM brakes seem to jam up in the heat.

I've reset the calipers and done some basic messing about but can't seem to stop them not returning into the caliper.

Any tips before I go Hope X2?

I've a low threshold patience for rubbish kit.


 
Posted : 25/06/2023 4:27 pm
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Never had a problem with Sram brakes - XO hydraulic, Force hydraulic, Force dual pivot rim brakes all work fine.


 
Posted : 25/06/2023 4:36 pm
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Its a known issue with (some?) sram brakes.  Been a  few threads on here about it and it happened to a pal.  The piston in the master cylinder expands / seizes / swells and jams on - the return spring is too weak to push it back

You can get an upgraded piston which cures it IIRC


 
Posted : 25/06/2023 4:39 pm
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Are these the ones with the plastic piston in the lever which swells up in the heat and makes your lever blades go floppy? That's a design classic.

Metal replacements are available on eBay.

Edit- Beaten by 30 seconds


 
Posted : 25/06/2023 4:40 pm
 rone
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Ah right oh.

Will probably just go hope now then.  Can't be doing with messing too much.

Thanks.

(One thing my lever has gone really tight not floppy)

That's a euphemism waiting to happen.


 
Posted : 25/06/2023 5:14 pm
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Dead easy to swap out TBH. Happened on my Guide RS many years ago in the heat. Swapped to the Gen2 pistons and been perfect since


 
Posted : 25/06/2023 5:19 pm
 rone
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Okay. Let me look into it.


 
Posted : 25/06/2023 5:22 pm
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Yup, the MTB brakes have plastic pistons which swell, it's a 5 minute job to change them IF you have a long/thin enough set of circlip pliars to reach into the barrel.

No idea about Rival's though.

The road brakes do have a wierd quirk where as the pads wear the freeplay in the lever reduces, so before the pad is worn out it almost locks on (never tried leaveing it any longer to see if it does get worse).


 
Posted : 25/06/2023 6:07 pm
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Had some elixirs do that. There’s only one real solution: angle grinder with a cutting disc along the master cylinder body and then straight through the calliper. Remove from bike. Place in bin. Buy something else.


 
Posted : 25/06/2023 6:16 pm
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The pistons in the master cylinders are made of plastic, overtime they start to degrade. Speaking 1st hand here, bike was in storage for 4 years and when I pulled it out and pulled the brakes they stuck on and stayed on, managed to semi free one of them up, the lever would return but it would take a good 5 minutes for the piston to return.

I stripped them down and found the plastic piston inside had essentially started to disintegrate and meld into its surroundings, nackered essentially. I looked at various options such as getting a few tools like circlip pliers and a rebuild kit at roughly £25 for each rebuild kit, £15/£20 on tools and roughly £5/10 postage. That's not including a bleed kit and fluid but I already had those.
You can get a metal replacement which would be the price of the original rebuild kit plus a fiver or so for each metal piston which would be the obvious choice so we're talking £75 roughly.

I had the old generic "SRAM Guide" model before they introduced all the T, R, RE etc and mine didn't have reach adjust, so I found bikeinn were one of the few places to just sell the levers and I bought 2x new Guide R levers for £120 inc postage.


 
Posted : 26/06/2023 10:10 am
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Also hot humid weather makes something to expand.  I had it on hols in Talk last year.  It is a known fault with Apex.  I had to release some of the fluid to get them working, then do a bleed when back in Blighty.


 
Posted : 26/06/2023 2:16 pm
 rone
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<p style="text-align: left;">It all rings true. I've fixed them with a hope brake order.</p>
But thanks.


 
Posted : 26/06/2023 2:31 pm
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Posted : 26/06/2023 2:44 pm
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rone
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<p style=”text-align: left;”>It all rings true. I’ve fixed them with a hope brake order.</p>
But thanks.

If you're going to bin them I'll buy them off you for spares.

I stripped them down and found the plastic piston inside had essentially started to disintegrate and meld into its surroundings, nackered essentially. I looked at various options such as getting a few tools like circlip pliers and a rebuild kit at roughly £25 for each rebuild kit, £15/£20 on tools and roughly £5/10 postage. That’s not including a bleed kit and fluid but I already had those.
You can get a metal replacement which would be the price of the original rebuild kit plus a fiver or so for each metal piston which would be the obvious choice so we’re talking £75 roughly.

Not sure what else you needed but the pistons and seals are about £5.50 a pair from China from a company called RISK components. Worth buying an extra set of seals at the same time (about a pound IIRC) as they can split whilst stretching them onto the piston.

Circlip pliers I sacrificed the cheapest set at B&Q and just ground them down until they could reach the circlip. £8 for a set of 4 .


 
Posted : 26/06/2023 2:59 pm
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I just had this last week, DB5s. Bleeding them solved the issue but looks from other comments might not solely have been that. If you've got the stuff lying around a bleed as 1st option could be quick remedy to at least rule that out.


 
Posted : 26/06/2023 3:08 pm
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I think you need to identify if it’s the lever or the caliper.

If it’s the caliper then the Hope RX4+ is probably an option.

If it’s the lever that’s going to be more tricky. I assume it’s the same problem as some of the old guides used to have with the swollen piston as mentioned above.


 
Posted : 26/06/2023 4:12 pm
 fs1e
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The Sram Level rear brake on my Giant Anthem has locked up twice at 2 year intervals. On both occasions I've changed the brake fluid and it's solved the problem. The front brake has been fine. Other than that the brakes have been excellent


 
Posted : 26/06/2023 4:13 pm

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