Author Topic: Brake pressure.  (Read 722 times)

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Offline GlenT

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Brake pressure.
« on: December 07, 2017, 11:37:32 am »
Hi guy's,
I have been itching to get my WR out and use it this summer. However, there is some odd behaviour from the brakes.
Last time I drove it (over a year ago) the pedal was slightly soft with the engine running. Now with the engine running the pedal is easily depressed all the way to the floor.
After switching the engine off I get 11 pumps of the pedal where it goes to the floor then I feel the pressure take up as per we should expect.
But if I leave the pedal for 5 or so seconds then try again, it will go to the floor.
At first I thought it was the accumulator, but I replaced this a number of years ago (probably only 1000kms) with an OEM one and also had the master cylinder bored out and a stainless steel sleeve inserted. This was done as the seals had perished and the master cylinder bore was pitted. Since the car is driven very rarely this re sleeving seemed prudent.
I'm going to start with a complete brake fluid bleed out but I'm not holding any hopes for a significant improvement with that. But it has to be done regardless due to the age of the fluid.
Anyone had a similar experience?
Cheers,   Glen

Offline RobClubley

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Re: Brake pressure.
« Reply #1 on: December 07, 2017, 11:44:19 am »
The brakes on mine feel pretty spongy at first but work when the pedal is pressed harder. Is that normal for these cars?
They've been bled 3 times now. New pads, discs and lines.
1985 ur quattro
2006 A4 3.2 quattro (Not to be modified by order of the wife!)
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Offline GlenT

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Re: Brake pressure.
« Reply #2 on: December 07, 2017, 11:56:46 am »
Hi Rob,
Both of my WR's had this slightly soft feeling until you pushed quite hard, then they would deliver the goods.
I think people get used to the sometimes over assisted brakes on late model cars.
The quattro's seemed to understate their own ability, yet performed well when you asked a lot from them.
I've had a couple of people comment on how spongy the brakes felt around town. I failed a WoF once as the testing guy thought there was something wrong. I put him straight.
Also, I took my current WR on a track day at Ruapuna a few years back where I consistently out braked my friends WRX STI RA lap after lap. Evidence they stand up well when pushed.
I currently have EBC green pads and rotors installed.

Offline colingrant

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Re: Brake pressure.
« Reply #3 on: December 07, 2017, 12:57:45 pm »
I had a very similar thing. Pedal would go to the floor after starting and afer a few pumps to the floor you would feel a dull thud and suddenly brakes would be normal ready for driving and they would stay ok till next time. As there is no connection between your foot and the brakes when working correctly only booster oil pressure, I decided it was the booster so I took it off the road to rebuild it That was 4 years ago . I got involved with a 39 Chevy..................Yeah I hear ya...........and have only just started looking at the quat again. I paid the price too. The fuel pump is dead so I hacksawed it open and found it seized with thick brown varnish. Couldn't believe it.  Replaced all the filters and got a fuel distributor rebuild kit and I'm on that at the moment. Could be fun. Watch this space.

Offline John Stone

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Re: Brake pressure.
« Reply #4 on: December 07, 2017, 01:48:51 pm »
Have look her Glen - the Isham Research site hosted by the late Phil Payne is now linked to Audifans....make a cuppa and begin reading


audifans.com/mirror/www.isham-research.co.uk/quattro/brake
86 WR
04 A3
05 V50T5

Online Lee

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Re: Brake pressure.
« Reply #5 on: December 07, 2017, 02:37:19 pm »
Just to add to this...I assume you all know Rob at Euroline in Auckland has a large box of accumulators and stuff collected over the years.
Might be useful ..... I hope he hasn't thrown it all out..

Offline GlenT

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Re: Brake pressure.
« Reply #6 on: December 07, 2017, 03:59:39 pm »
Have look her Glen - the Isham Research site hosted by the late Phil Payne is now linked to Audifans....make a cuppa and begin reading


audifans.com/mirror/www.isham-research.co.uk/quattro/brake
Thanks Colin,
I've read most of this over the years. Really sad to hear of Phil's passing a while ago, he was a guru.
I have read of other people having a similar but not the same issue. It could be any of the main components at this point.
Normally there is some indicator as to which component it could likely be, but this is plain weird.
I may just have to start with the easier items, such as remove and inspect the master cylinder and go back from there.
If I could try a known good accumulator after that it would help.

Offline GlenT

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Re: Brake pressure.
« Reply #7 on: December 07, 2017, 04:03:26 pm »
Just to add to this...I assume you all know Rob at Euroline in Auckland has a large box of accumulators and stuff collected over the years.
Might be useful ..... I hope he hasn't thrown it all out..
I'll keep that in mind. Thanks.
Mind you, if it is the accumulator I'd rather just buy new if they're still available.
Last one I bought was NZ$400 from Archibalds.

Offline GlenT

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Re: Brake pressure.
« Reply #8 on: December 14, 2017, 01:49:22 pm »
Took the master cylinder and proportioning valve into a local brake service center here in Dunedin, they couriered it to a firm in Auckland over night. 
After stripping they found the master cylinder bore was scored and will need re-sleeving.
Good thing is, something was found. Better than having to dig deeper.
So they'll re-sleeve the MC and re kit both items then I'll assemble, flush out the calipers and lines (fingers crossed). :)

Offline GlenT

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Re: Brake pressure.
« Reply #9 on: December 20, 2017, 11:08:26 am »
Well. I picked up the master cylinder and proportioning valve from the brake shop yesterday.
What they handed me made my blood boil!
The firm they sent them to for refurbishing had cut the valve casing off the proportioning body with what appeared to be a hacksaw, worked on it then shoved it back on and welded up where they had cut. They had also cut into the cast body with the hacksaw.
They have bruised the master cylinder body where it fits into the hydraulic servo with a hammer. Obviously been hitting it whilst trying to remove the old sleeve.
Went back in today after cooling off last night and had a lengthy/heated discussion about resolving the issue. They initially offered to refund the cost to refurbish the proportioning valve and send my one back up. I argued that this would leave me far worse off than before I went in as I would have no valve. A new after market one is US$260 plus shipping/tax. Nearly NZ$500.
I left agreeing to let them contact this company up north to see what they were going to do as this is a necessary step if things were to escalate.
Just had a call from them saying they would give me a full refund ($544).
So now I have to fix their cock up and make it perfect. I can do that, but it's time which equals money.
Ahh, that feels slightly better. :-\

Offline slowburn

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Re: Brake pressure.
« Reply #10 on: December 20, 2017, 11:31:12 am »
That sucks,sorry to hear that,i can't stand it when people take no care with a job...my old girl looks rough,and she is on the surface, but underneath she is solid.....
89 200 quattro exclusive(gone to a better place)
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Offline RobClubley

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Re: Brake pressure.
« Reply #11 on: December 20, 2017, 11:31:58 am »
It's so annoying when workshops do shoddy work.
Especially on hard-to-get parts.
1985 ur quattro
2006 A4 3.2 quattro (Not to be modified by order of the wife!)
quattro project

Offline GlenT

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Re: Brake pressure.
« Reply #12 on: December 20, 2017, 02:54:29 pm »
It's so annoying when workshops do shoddy work.
Especially on hard-to-get parts.
Exactly.
Will probably buy one of the after market proportioning valves and either get the actual valve off it and replace the one on mine or, just fit the new after market unit. They look pretty good.
I can spend a bit of time gently draw filing down the wee bruises on the MC with a small fine file and it will come up fine.
I just had trouble getting it into their heads that I wasn't prepared to fit these back onto the car as they were. They said they'll be fine, and you wont see them etc etc. I said I'll see them and the point was I was charged a reasonable sum to butcher my parts that are hard to replace.
Some people just don't care. Then they meet me and their day goes down hill. ;)