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Air in the brakes


Grizzlee

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Went for a play around the lanes of Beeston at the weekend and noticed the brakes were not as good as they should be on my '91 SE, lot of travel spongy etc.!!

So spent several hours on Sunday bleeding the brakes by the traditional method but couldn't get rid of the air :(  

It's been a long time since I had to do this to a car but remember having more success last time. I even did the block of wood trick overnight but it was the same again the following day.

My question is could this be a sign of the master cylinder being b*******ed, if so would you repair it or replace, I can't believe the air coming out is trapped, it has to be getting in somehow (I think, possibly, maybe)

Thanks in advance.

Graham

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Since you say it is a long time since you did it, then your brake fluid may have gone off - it does need replacing very now and then!  Amongst other things, you could have "boiled" it with some spirited driving, or moisture could have got into it.
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This could well be the case, but I put 1.5 Litres of fluid through it and with it being a simple system thought that should have cleared it. The pedal does feel better but still travels a long way :(

Cheers

Graham

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It's a good idea to check the wheel bearings too. They can give the impression that your brakes are spongey if there's play in them.
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Graham - did you use fresh brake fluid, or had it been lying around for a while?  If it wasn’t fresh, it could have absorbed some water vapour whilst lying in your garage.
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It's a good idea to check the wheel bearings too. They can give the impression that your brakes are spongey if there's play in them.

Guys,

I did check the bearings after reading some of the posts on here and the fluid is new. The bleed tube I'm using is clear, so you can see and for that matter hear the air coming out. It just keeps on coming, which makes me think it's "new" air getting in somehow rather than trapped air.

Thanks

Graham

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so what your saying is you are pumping air bubbles entrained in the brake fluid?

does the reservoir have air bubbles in it?  when you release the peddle can you see the bubbles moving back up the transparent pipe or do they remain stationary?

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How far off have you backed the bleed nipples? Back 'em off too far and air can travel down the threads and in to the caliper. I only ever back mine off about half a turn, and probably not even that...
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so what your saying is you are pumping air bubbles entrained in the brake fluid?

does the reservoir have air bubbles in it?  when you release the peddle can you see the bubbles moving back up the transparent pipe or do they remain stationary?

This is exactly the case, bubbles entrained in the fluid.

There are no bubbles in the reservoir and I always close the bleed nipple before releasing the pedal.

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How far off have you backed the bleed nipples? Back 'em off too far and air can travel down the threads and in to the caliper. I only ever back mine off about half a turn, and probably not even that...

I also only back them off a little way then close them before the pedal is released.

My 10 year old daughter is has got huge muscles in her left leg   :D

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I had spongy  pedal problem last week, bled brakes  5/6  times pumping pedal and cracking nipple off through a clear pipe into a bottle no air came out  , pedal still travelled and was spongy! my car had been stood a few years so ended up changing the brake fluid for what it cost , using a pressure bleeding thingy off the tyre valve, after a load of fluid came out of the front caliper a load of air came through the pipe... brakes  now 100%...

to work out if your prob is front or rear and  if you have rubber flexy hoses clamp 2 off and check the pedal you should be able to work out where the problem lies?

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I had spongy  pedal problem last week, bled brakes  5/6  times pumping pedal and cracking nipple off through a clear pipe into a bottle no air came out  , pedal still travelled and was spongy! my car had been stood a few years so ended up changing the brake fluid for what it cost , using a pressure bleeding thingy off the tyre valve, after a load of fluid came out of the front caliper a load of air came through the pipe... brakes  now 100%...

to work out if your prob is front or rear and  if you have rubber flexy hoses clamp 2 off and check the pedal you should be able to work out where the problem lies?

Jeff,

I've just got one of those easy bleed things so will give it a try now after wasting 2 days on the old method. My hoses are braided I'm afraid.

Cheers

Graham

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...errr...this may sound stupid but after I'd had my brakes done (by someone else :blush: ), they felt spongy on the test drive.

I returned the car to be told, "...don't worry, they'll bed in."

I had my doubts, especially as they didn't feel any different after the 60mile journey home.

However, they pedal did harden, much to my surprise, over the next few blats.

HTH

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My 10 year old daughter is has got huge muscles in her left leg   :D

Training her to be a rally driver, are you?

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