I have 2 bikes with the SRAM guide R brakes.

on one bike the wheels barely turn (when spinning them) when the bike is pulled out a warm garage (with no windows), the levers don’t return and the bike is barely rideable. it was probably about 35 deg C in there the last time i tried.

The other bike however is entirely unaffected, they are both the same age. What gives? is this a known fault?

thanks

Yes, known fault with the lever piston. A seal or something inside swells in the heat and it jams the brake on. I’ve got it on one of mine.

There’s an updated piston fix, but you can get warranty fix/replacement in theory (just looking into that myself).

The newer updated Guides with S4 calliper I think should have the new lever. Got them on another bike and not had any issues with it in the heat.

Piston in the lever can swell in heat causing the brakes to lock. Loads of Guides in our group in Finale failed that way this year. Warranty job.

My RSs were just out of warrenty. You can get a Gen2 piston on ebay for £16 delivered within a week from Taiwan.  I didnt want to be without the bike so sanded the piston slightly and that worked until the new piston arrived. Hardest bit is removing the spilt ring.

I’ve emailed SRAM UK, and there is no recall on these – madness as so many are failing in the heat.  They have offered to take mine back for warranty as a matter of courtesy, but I’d need to take it in to a bike shop as they deal with trade only.

For the £16, and less than an hours time, I’d rather do my repair myself, as I have done on the rear. The front has been fine so far. I have a spare ‘sanded down’ piston if the front fails.

The good thing is I now know how to strip and rebuild the lot as it’s also been my first time bleeding the brakes in 2 years – the fluid was still clean.

I have had the same problem on my Avid Elixirs; oh and whatever the Avid brakes I had before them – Juicy 7’s I think?

I solved the problem with the Juicy’s by swapping them for SLX.
When I have the funds, I’ll be doing similar with the Elixirs.

Staying clear of SRAM supplied brakes seems like the best fix, as far as I can tell…

Never had this problem with the Avid X0s, X0 Trail (same calliper as the original Guide), or the new design Guide RSC.

Only the one with the known fault which in my case is also a Guide RSC, but pre-S4 calliper.

And SRAM Guide (and the X0 Trail) are miles away from the old Avid stuff.

Anyway, I’m told the RSC is easier to fix as there’s no circlip ring due to the bite adjuster holding whatever it is in place instead, or something like that. Still though, if it’s a known fault it should be a warranty / Consumer Rights Act job.

It’s the piston in the lever, rather than the caliper, dk – so it wouldn’t have affected XOs

Funny – all the reviews of Guides have been massively positive, but I know lots of people unhappy with them for this reason and other issues.

It’s the piston in the lever, rather than the caliper, dk – so it wouldn’t have affected XOs

That’s what I mean, the lever pistons are different in them all (I just chucked in the calliper reference to distinguish the X0 (Elixir based) from X0 Trail (forerunner to the Guide). The problem is the original piston in the lever of the Guide.

Funny – all the reviews of Guides have been massively positive, but I know lots of people unhappy with them for this reason and other issues.

They’re great brakes and I still love them. This issue has only really come up for me due to the hot weather, and it’s hit a few of my friends also. Just needs the lever piston replacing with the fixed version. Other than that I don’t have other issues except the reach adjuster is a bit rubbish and they should have used the one from the X0 Trail which is much better. Though it works (and Guide RSC has a much better bite adjuster).

Well known problem.  Easy enough to fix – I plan on trying it this weekend with mine.  Good how to do it video here (among loads on YouTube).

https://youtu.be/eStqmCu7NOI

If I take the bike back to Halfords the brakes will likely be working fine. I’m concerned they won’t believe there is a fault. What’s the best way to proceed other than showing this thread ?

Had the same with my RSC . The lever wouldn’t budge.  The caliper was “fortunately” open.

Replaced with XT four pots.

More solid feel to them, prefer Shimano levers, too. And the bleed process is a doddle.

I had the exact same problem with mine, easy fix, buy a pair of Shimano’s, been great ever since.

ps sold the guides on which offset the cost of shimano’s!

Some of us don’t get on with binary brakes and like a bit of modulation 😉

Fossy, did your eBay replacement arrive? How was the quality?

Could you share the link to the seller please?

Thanks

I think I might have the same problem  with Guide R’s but maybe a smaller scale failure ?

The bike is still ride-able but the front brake doesn’t feel good.

When you pull the front brake it does nothing for the first few mm then when the brake lever gets closer to the bars it only then starts to bite. But the initial pull does next to nothing. They’ve been bled twice recently as well.

Anyone know what this is ?

My G2 piston arrived within a week from Taiwan

A seller here

https://www.ebay.co.uk/itm/Sram-Avid-Piston-Assembly-and-Return-Spring-for-GUIDE-R-RS-RE-DB5-Qty-1-VER-G2-/273110942361

@trevmccdonald

Sounds fairly normal for Guide / SRAM brakes. There’s usually a fair bit of travel before they bite. Though the RSC have bite adjust.

Though check the pads. If fairly worn it may not be adjusting for wear quite right.

It’s likely different to the sticking issue. When they stick the piston in the lever won’t retract and the brake is binding on the disc, and when it’s really hot it may lock solid.

I’ve found a quick grab of the brake and release sometimes unsticks it briefly.

@fossy – seen that posted elsewhere. Is there a guarantee it’s the genuine part and the fixed version beyond them saying V2? Doesn’t show the SRAM part number. Also doesn’t mention RSC only R/RS/RE/DB5

i’ve warrantied mine through my LBS. it’s a known fault and they will change the levers. However, a few weeks wait for the levers as I assume there have been a lot of warranties in the last few weeks.

@trevmccdonald

That’s a different thing and a trait of the guide brakes.  As the pads wear the calliper does not adjust accordingly and the lever throw gets ridiculous.

Annoying but easy to work with if you have the pad spacer that comes with the bleed kits.  Wheel out, pump the brakes until the pads are almost touching (pistons will not pop out don’t worry) and then space them with the spacer.  Repeat 2 to 3 times.  Replace wheel and voila.  There is a youtube vid with a SRAM tech demonstrating this – think he calls it ‘pad advancement’.

May take some playing around to get the pistons advanced sufficiently to reduce lever throw without there being disc rubbage, but better than chucking in new pads every time it happens!

Ok some good news and some bad news

The good news is they have agreed the brakes are faulty and they are going to replace the pistons in the levers themselves at the shop

the bad news is Halfords are going to do the repair so my expectations of a quality repair are very low lol

Weird. I’d just expect a straight swap. Can’t see any Halfords “technician” capable of doing the repair. Most stuff they send off if it’s beyond changing brake pads or fixing the forks they put on backwards in the first place.

@fossy thanks for link and update. Unfortunately that one is out of stock so ordered this one https://m.ebay.co.uk/itm/Sram-Guide-RSC-Ultimate-Piston-Assembly-and-Return-Spring-Qty-1-VER-2-Gen-2/273281825150?hash=item3fa0ddb97e%3Ag%3AIOkAAOSw1qtbRx3D&_nkw=sram+guide+piston&_from=R40&rt=nc&_trksid=p2332490.m4084.l1313.TR4.TRC0.A0.H0.Xsram+guide+p.TRS0

Hopefully that will fix it. It’s strange it only affecting on lever and first time in three years of having them.

^^ Those are different to the oos ones fossy linked to though? Only fitting the Ultimate and the RSC…

Update.

Part arrived this week from China for my RSC’s. Spent a good three hours messing with it yesterday. The strip and build is dead straight forward but couldn’t get the lever to move properly. It wouldn’t retract after being depressed.

The plastic piece is near identical so after lots of messing tried swapping the spring with the old one and it worked!

Good stuff all fixed.

I couldn’t be bothered waiting, and I needed to bleed the brakes anyway as they had not been done for 2 years (fluid was clean still).  Was a good way to see how they worked.

By the way, as the pads wear, the travel on my levers doesn’t change – it’s just the same with new pads as it is with worn ones – didn’t realise how quickly my rears wore out at the start of the year in slop – they went within 2 rides.

This has also affected mine (Rsc with S4 caliper), ordered the same part as Leonthepro after first striping it down and slightly sanding the piston, but got impatient with one of the seals and damaged it whilst removing it, so hopefully the new piston will sort it quickly.

Why go eBay when Bikeinn do it and it’s the genuine article?

Delivery within a few days too.

Couldn’t find it on their website, what did you search for?

Posted the part number here a while back.

5878574

Their site says no products found?

^^Ditto.

My guide RS’s went back about 4 weeks ago for warranty repair. Still waiting.

good brakes when working but I’ll stick with Shimano in future.

Piston arrived from Taiwan this afternoon, swapped it with the original in about 20mins, will refit to bike and bleed tomorrow, but everything certainly feels good.

I’m at Crankworx at the moment and just heard the SRAM manager say to one of the techs after they pulled a set of brakes off “I don’t want to see any of those out here, make sure you put them in the bin in the truck”

Apparently they’ve had a lot back.

As said, it’s a fault they have fixed. Shouldn’t be a problem once you get the fixed piston.

So it’s getting warm this weekend and I haven’t fixed my sticky Guide RSCs from last year as they started working fine once cooler temperatures.

Found there’s a mega thread on this in MTBR – https://forums.mtbr.com/brake-time/guide-rs-levers-not-returning-replaced-under-warranty-1011229.html

Mentions ali machined alternative piston and seems there’s a fair few about, for example – https://www.ebay.co.uk/itm/Brake-Lever-Internals-Rebuild-Part-Piston-Assembly-for-sram-GUIDE-Level-db5-Hot/132779572591

Wondered if anyone’s tried them?

Also, not sure if you get two in the pack or one. Says “1Pcs Brakes Piston Assembly” but photo of a bag with two in. I’ll need two to fix both brakes.

Think this might have recently started happening to my front brake, lever goes stiff in hot weather and brake locks up. If it’s happened to one is it just a matter of time before it does on the other side?
I found flipping the bike upside down mid ride freed it??
Bike is 2.5 years old.

Just experienced the same issue with my Guide Rs this weekend after the London to Brighton BHF ride.
Both brake levers sticky and notchy when warm and right wouldn’t release fully so rear brake was dragging.
The adjuster /cam on the rear lever seems to have moved as well.
So is the Taiwan eBay revised lever plunger still the best fix?
What else do I need to strip and rebuild?

It affects Levels as well. Both mine did it. Replaced with XT.