Brake bleeding woes

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 G. Tiger, Esq. 15 Jul 2020

Evening all,

Back brake on the mtb was a bit soggy. Pads are worn - put new ones in, still soggy. Thought I'd bleed it. Still soggy. I've bled them before, but not for a while, so did it again just to be sure. Still soggy.

The lever is coming all the way to the grips and sometimes squishing my fingers so not ideal! It's working a bit. It will stop the wheel from spinning freely, but with any weight in the bike I can easily rotate the wheel. 

With the lever off the handlebars I can make it bite harder, but that's not long term solution! I've mucked about with the reach adjustment to try to get more pressure on, but no luck.

Any ideas? Brakes are avid elixirs if that's any help, six years old. Do I suck it up and buy a new lever unit? Entire brake set up?

Cheers 

GTE

cp123 15 Jul 2020
In reply to G. Tiger, Esq.:

I have the same brakes and had similar 'spongey' problems. There is a little hex bolt in the lever itself which adjusts the 'throw' of the brakes and by turning it in it really firmed up the brakes for me.

Cheers

 balmybaldwin 15 Jul 2020
In reply to G. Tiger, Esq.:

I'm not familiar with Avids, but firstly before you do anything else put the old pads back in while bleeding so you don't accidentally contaminate the new ones!

Have you refreshed all the fluid? it gets contaminated over time that can lead to sponginess so worth doing a complete flush if you haven't.

If you have, are you sure you have the right fluid? different manufacturers use different fluids and aren't always compatible (I know my shimanos use mineral oil and my formula 1s use dot4 (I think it's that way round))

Depending on how elixirs are bled, usually moving levers around the bar, or putting the bike at an angle will help minimise the chance of air pockets in the system when you are bleeding which is most probably your problem. You need to make sure the bottom valve as actually at the bottom and the top valve (bleed screw) actually at the highest point

https://www.youtube.com/watch?v=IoaPUw5DliA&feature=youtu.be

In reply to cp123:

That's what I meant by reach adjustment. Tried that and ran out of bolt before getting any sensible improvement 

Gte

 Dave Todd 15 Jul 2020
In reply to G. Tiger, Esq.:

We just happen to have 4 bikes in our household with Avid Elixirs (5s and 3s) so I've done a lot of bleeding of Elixirs over the years.  As a lockdown task I've just bled of 3 of the bikes and managed 5 very good brakes, and 1 'still a tad spongy...'

My tips;

(1) Get the 'pro-level' bleed kit - the basic bleed kit is awful.

(2) Spend ages making sure that you've got all the air out of the lever end of the system.  If need be tip the bike up on its back wheel (like a 90 degree wheelie) and pump the brake lever for a minute to see if there's any increase in spongyness - it there is then extract the bubbles from the lever again.  Repeat as required.

(3) This is the process that I use -  youtube.com/watch?v=bZylrZvICrY&

There's a definite 'knack' with Elixirs, but if you manage a good bleed then they're absolutely fine (for the kind of riding that I do)

Good Luck!

In reply to balmybaldwin:

Yup, done all that. Flushed the whole fluid twice. Had the bike on the stand with the handlebars in the air and the rear caliper way down low. Took the lever off to get it even more vertical. Tapped my way all along the tubes to loosen any bubbles 

Used a spacer rather than leaving the pads in (tried cleaning off the old pads by burning off the crap - exploded one as it clearly still had water in somewhere)

I'm using dot 5.1, which is the recommended fluid. 

I'm not keen on having to replace the brakes, but there's nothing to stop me! (Groan). I already need new bb and probably a chain ring /drive train overhaul, and some suspension fork fettling...

Gte

 balmybaldwin 15 Jul 2020
In reply to G. Tiger, Esq.:

If you are going for replacements I don't think you can go wrong with Shimano XT's Much cheaper than my Formula brakes but at least as good (and more adjustable and a dream to bleed in comparison).

In reply to Dave Todd:

Third time's the charm right?

It worked. Briefly.

Whenever I was pressurising, or de pressurising I could hear something wet and bubbly by the brake lever. Completed the bleed procedure, and it worked. Put the pads back and the wheel on and it worked. Took the bike off the stand and it didn't...

Trip to lbs it is then. Thanks for the advice guys.

Cheers 

Gte 

In reply to G. Tiger, Esq.:

> Yup, done all that. Flushed the whole fluid twice. Had the bike on the stand with the handlebars in the air and the rear caliper way down low. Took the lever off to get it even more vertical. Tapped my way all along the tubes to loosen any bubbles 

> Used a spacer rather than leaving the pads in (tried cleaning off the old pads by burning off the crap - exploded one as it clearly still had water in somewhere)

> I'm using dot 5.1, which is the recommended fluid. 

> I'm not keen on having to replace the brakes, but there's nothing to stop me! (Groan). I already need new bb and probably a chain ring /drive train overhaul, and some suspension fork fettling...

> Gte

Degradation of the cables?

In reply to DubyaJamesDubya:

What cables? It's hydraulic. 

Unless you mean the tubing, in which case - maybe? How would I test it? In fact don't worry  - i'll ring the shop instead!

Thanks 

cp123 16 Jul 2020
In reply to G. Tiger, Esq.:

Sorry I missed that bit. I will assume you have relaxed the bolt, bled the brakes then tightened it up after. Reading through your posts you seem more experienced at bleeding brakes than me - the only advice then is maybe speak to a shop as they might be able to do it for less than the cost of a new brake.

 Herdwickmatt 16 Jul 2020
In reply to G. Tiger, Esq.: I’ve had the same woes with elixirs. Bled them myself a few times but never very successfully. Also had a bike shop do it with mixed success

 gimmer 16 Jul 2020
In reply to G. Tiger, Esq.:

Hi,

Just a thought, could there be a leak in the system where air could be getting in?

During lockdown I started doing long needed bike maintenance and found an issue with my 10 year old Shimano XT brakes.  I bled them, the levers felt firm but had virtually no power at all, and then they'd become soft.  After much fiddling around, repeated bleeds, replacing all the fluid etc I spotted that with the bleed block in the caliper, when I pulled the lever hard there were bubbles coming out around the pistons!  Turns out that the piston seals were worn out, not surprising given their age to be honest.

I replaced both calipers with the latest Deore models, and now they working perfectly.  On reflection I think it would have been virtually the same cost just to buy an entire new set of brakes.

Hope that is useful

Cheers  

 LastBoyScout 16 Jul 2020
In reply to Dave Todd:

> (1) Get the 'pro-level' bleed kit - the basic bleed kit is awful.

I've got the pro-level bleed kit and I still thought it was rubbish - leaked air between the syringes and tubes. My top tip would be to glue them together before you start, so they can't leak.

Mines a few years old, though, and looks like they might have updated it.

> (2) Spend ages making sure that you've got all the air out of the lever end of the system. If need be tip the bike up on its back wheel (like a 90 degree wheelie) and pump the brake lever for a minute to see if there's any increase in spongyness - it there is then extract the bubbles from the lever again.  Repeat as required.

I've not done Avid brakes, but have done the Hayes ones on my sister's bike.

If all else fails, usually injecting a full measure of fluid from the caliper up to the level will help.

Also the "pull fast, release slow" technique of pumping the brake lever can help clear air bubbles.

Apart from the leaky pistons mentioned, I once had an issue with a pin hole leak in the front brake hose on my bike - replaced hose, bled it, problem solved.

When I get time, I'll be upgrading the mechanical brakes on the CX bike to hydraulic - that'll be a whole new world of fun, I expect!

 Frank4short 16 Jul 2020
In reply to G. Tiger, Esq.:

If they're continually spongey after the bleed, probably one of the best things you can do is position the bike in such a way that there's continuous upwards travel between the hose and the brake lever. Which is will most likely mean having the bike in a bike stand at somewhere between 30 and 60 degrees above horizontal with the rear wheel being the low point, and is also no mean feet without a stand. Adjust the lever on the handlebar so it's horizontal (or whatever the correct position is for filling fluid)

Next step is to open up the fluid fill on the lever and fill with fluid, put an elastic band on the brake lever pulling it in and leave sit for 12-24 hours open. This will allow any air bubbles in the line to gently rise to the fill point and come out. (this is quite easy with shimano's fill funnel though i can't talk about Avid, as i haven't touched a pair in donkeys years).

Hopefully by that point you should have removed the majority of air out of the system. If they're still spongey it means there's air trapped in the caliper. Which means you'll have to get creative in terms of the positioning of the bike alternating various positions to get it in a position where the air pocket in the caliper is no longer the high point in the caliper. 

Post edited at 11:34
In reply to Frank4short:

A recent survey of two LBS said "buy new ones. Don't throw good money after bad. There's a reason they don't sell/support them any more..."

Interestingly, on one of my first rides out yon the bike a random passer by berated me for my choice of brakes (though they came with the bike), citing their maintenance issues amongst other things. Six years later, maybe he was right. However he also told me that my forks Were bottoming out, which was clearly untrue... 

Anyway / recommendations for a replacement that is if similar performance and won't break the bank please?

Thanks 

Gte 

 gethin_allen 16 Jul 2020
In reply to G. Tiger, Esq.:

I've been fighting on and off with some avid elixir brakes for years. I bleed them, they work for a while and then despite keeping the bikes in the house they absorb moisture and pump out. And so the cycle continues. I've been talking about replacing them with Shimano for years now but I rarely use my MTB these days and it's 10 years old so can't justify spending money on it. I have a 15 year old (maybe more) Shimano XT 4 pot brake in a box somewhere but I'm not sure if you can still get the pads.

 LastBoyScout 16 Jul 2020
In reply to G. Tiger, Esq.:

Shimano or Hope would be the way to go.

I actually have a spare Shimano back brake you're welcome to have. I was given it, but don't need it, so happy to pass it on. Seems ok, but needs new pads. M445 lever and M447 caliper - you may be able to get a matching front one.

In reply to LastBoyScout:

Spare brakes sounds good. Not least because it makes a decision for me!

I'll send you a message 

Gte

In reply to G. Tiger, Esq.:

> What cables? It's hydraulic. 

> Unless you mean the tubing, in which case - maybe? How would I test it? In fact don't worry  - i'll ring the shop instead!

> Thanks 

Yeah, sorry, should have said hoses.

In reply to G. Tiger, Esq.:

I don't know about Avids but I had a Hope Race Evo that was spongy after multiple bleeding even though many previous bleeds/fluid changes had firmed them up nicely. I though maybe the seals in the master cylinder had started leaking (so some fluid slips past the piston rather than moving the pads. I replaced the seals, re-bled and now they are perfect again. Perhaps it is the seals? Cheaper than new brakes.

 GPN 18 Jul 2020
In reply to harold walmsley:

Agreed. The squelchy noise and deteriorating performance suggests that there’s a leak in the master piston seal. I’d probably just replace them with Shimano ones!

 Frank4short 19 Jul 2020
In reply to G. Tiger, Esq.:

Shimano Deore all day long, great value for money and they work really well and are extremely easy to carry out maintenance on when (rarely) required. 

 mike123 19 Jul 2020
In reply to G. Tiger, Esq.:

i have a mate who owns a bike shop, if anybody asks them to work on avid elixirs they advise against it and to replace with new shimano or Clarke , as the amount of time it takes him or one of his mechs to get them sorted , or fail to ,  costs more than a new set of brakes . The three step plan to sort avid elixirs :

1. Remove brakes from bike .

2. Throw brakes in bin .

3. Fit shimanos.

check out Clarke brakes on eBay / wiggle / Halfords . I got a front brake for one of the kids bikes for silly cheap from Halfords last year  . Again , bike shop Brian reckons they are as good as shimano for less money , 


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