brake failure on open road - help

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Shaundon
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brake failure on open road - help

Post by Shaundon »

Took the van out for a test run yesterday and on the way back the brakes failed while driving, luckily down a quiet country lane. I hate to think what would have happened if this had been on the steep winding roads i was on around beachy head on bank holiday monday.

Peddle went soft and straight to the floor. Pumping 2 or 3 times regained stiffness for a few secs but next press its gone soft again. Limped home as was only a few hundred meters away.
Went to look at them again today and the braking is fine again!!

Obviously i cant risk this happening again so need to get it fixed. Reading on the forums here it could have been vapour lock from the fluid boiling but i wasnt going that hard or fast , so why would that suddenly start happening?.

I jacked the wheels up and spun the wheels one by one and the offside front seems to bind a fair bit after pressing the brake - could this be causing the fluid to heat up. (The disc didnt seem much hotter than the nearside one).

Any advice would be greatly appreciated.

S.
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armyphil
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Re: brake failure on open road - help

Post by armyphil »

Popped wheel cylinder?
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Shaundon
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Re: brake failure on open road - help

Post by Shaundon »

could be ?

Is there a way to tell if this is the case?

S.
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R0B
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Re: brake failure on open road - help

Post by R0B »

When did you last check your fluid level.
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AdrianC
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Re: brake failure on open road - help

Post by AdrianC »

First things first - CHANGE THE FLUID. It should be done every two years. It rarely is. It's a quick, easy and cheap job. Check everything thoroughly at the same time. See if the rear cylinders are leaking. Make sure nothing's seized. Make sure everything's wearing evenly. Make sure all the flexis are good.

If everything looks good, and you've got new fluid in, then there's not much more to be done short of trial-and-error changing of components, or waiting to see if the problem recurs/develops.
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Shaundon
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Re: brake failure on open road - help

Post by Shaundon »

fluid level hasnt moved and checked all round for leaks with no sign-

wondering if this could be a fault with the master cylinder?
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Shaundon
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Re: brake failure on open road - help

Post by Shaundon »

the fluid was mostly replaced when the clutch slave cylinder went a couple of years ago and i added another litre recently when bleeding the front nearside caliper after changing the hose on it. havent bled out all the brakes though so i guess old fluid could still be down the other pipes?

surely though old fluid couldnt cause such a massive brake failure without another problem being present?

The brake fluid in my daily run around hasnt been changed in years and it is driven alot harder than the van and ive never had this sort of problem.

will replace it anyway along with rest of the hoses etc. but im reluctant to just wait for this to happen again as could be nasty next time!
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AdrianC
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Re: brake failure on open road - help

Post by AdrianC »

Shaundon wrote:the fluid was mostly replaced when the clutch slave cylinder went a couple of years ago

So due for replacement, then.

But - yep - even a bit of old, damp, fluid will introduce moisture, which can boil. I'm not saying that IS your problem, but it's always a good first place to start when you've got old fluid in a system that's suddenly and oddly giving the symptoms you describe.

The brake fluid in my daily run around hasnt been changed in years

Get it done! Not only can and does it boil, but it's the main cause of corrosion in brake cylinders and calipers.
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vanisveryrusty
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Re: brake failure on open road - help

Post by vanisveryrusty »

Brakes is brakes.
Forums are great for advice.
Unless you are a qualified or very experienced amateur mechanic...................
With an intermittent brake failure fault.
GET A PROFESSIONAL FIX.
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Shaundon
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Re: brake failure on open road - help

Post by Shaundon »

I agree - but ive been to many qualified mechanics in my time who have either not been able to fix or have said they have only for the fault to persist , so id like to get the opinions of real experts on these vans (ie the folk on this forum) before taking it further.
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Shaundon
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Re: brake failure on open road - help

Post by Shaundon »

ok i removed the offside front wheel and pads that was sticking and it has freed up the disc so it now rotates freely
(pads were stuck well in and hard to remove)

here is a picture of the caliper - doesnt look good to me, seal looks a bit gone?
Image
also there was no anti rattle shim in there

do you think i need a new one or can this be rebuilt with one of the kits.
1984 1.9 petrol wbx DH with a pierburg carb , LHD westfalia club joker.

Shaundon
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Re: brake failure on open road - help

Post by Shaundon »

got the caliper off but its a bit off a mess - cant get pistons out as they seem seized and the bleed nipples are all mangled and stuck in as well. So god knows when the fluid was last changed/bled on it.

So i am going to get a new set of calipers for the front , anyone know if these ones on vwheritage are any good??
http://www.vwheritage.com/vw_spares_Cal ... tartPage=1

Also should i be replacing the brake master cylinder as well? Is it possible it failed and let in some air without leaking on an intermittent basis?

S.
1984 1.9 petrol wbx DH with a pierburg carb , LHD westfalia club joker.

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REGGAJ
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Re: brake failure on open road - help

Post by REGGAJ »

Try Here :ok http://www.brickwerks.co.uk/index.php/t ... parts.html" onclick="window.open(this.href);return false;
Image

Shaundon
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Re: brake failure on open road - help

Post by Shaundon »

yeah i usually use brickwerks - its just id have to post the old one back for the refund and wait for delivery while vwheritage are just down the road so can pop down and pick one up. However found out eurocarparts do a recon unit which is even closer so nipped down and got it today and its on with new hose as well.

Now just need to know if i should replace the brake master cylinder too ? -

Once its all back together im going to take the van down to my local garage and explain what happened and get them to test the whole breaking system as i dont want to experience this again!.

S.
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Re: brake failure on open road - help

Post by nevill3 »

My local VW specialist ordered a new caliper for me, and I didn't need to send the old one back, you could also try your local motor factors too.
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