Pulsating brakes

[MrJee]

Hello, i have a problem with my 3b s2, I recently replaced a power assist hose and had some trouble right after with the (!) symbol coming on every once in a while. I checked all fluids and everything is fine.
It might suggest the brake bomb, but i can do 50 pumps before it gets stiff.
The brakes are also new front and back. I was driving today and when i turned it off, i tried to test the bomb again.
It did 50 pumps, and when i turned on the car, the brake pedals pulses back.
Even when standing still it pulsates back, do i need to bleed my brakes? Or is my bomb ruined? I dont understand this, because the brakes were fine, just a little beep and that ! sign.

[tajgreidotu]

I had the same symptoms, time to chage you ps pum seals!!

[MrJee]

Did that solve the issue? I hope i havent ****ed anything up, im not sure if i should drive it now, the light is flashing constantly in the dash.

[Rusty]

I had this for a bit on and off. Replaced the servo and all sorted. I think it's the system trying to pressurise and failing due to a poor seal in the system. Once pressurised, it'll work fine. Might be time to go vacuum assist...

[Error404]

servo

[MrJee]

So the servo pump seals might have broken when i did the test? I am going to have the codes checked out now and see what they say.

Is it any chance this might bleed itself ?

[jade]

So the servo pump seals might have broken when i did the test? I am going to have the codes checked out now and see what they say.

Is it any chance this might bleed itself ?

It's self bleeding, your best bet is to convert to Vacuum as the OEM set up is problematic with poor pedal feed

[Error404]

There will be no codes for the hydraulic system, you mostly need to use common sense & good old fashioned deduction on these motors

The servo is quite easy to replace, I have a spare if you need it - won't be any use to me as i am going to upgrade to vacuum assist in the new year. Let me know if its of interest.

[MrJee]

Thanks man, i do have a spare servo pump and bomb lying around from when i had to replace the pas hose. So replacing the servo should fix this? Sorry i am new to these cars as i just picked up a 1990 3b s2. I just had a large service done, just need to fix this little issue

[Error404]

you can try flushing the hydraulic fluid, that can sometimes recover them but it is borrowed time if they do, failure will stalk you

[MrJee]

Already tried flushing, seems there was some atf fluid when i purchased the car, when we did the hose swap i put in the correct green Audi fluid.
Tried re bleedimg the steering, no luck.
Also if i try to stomp hard on the brakes, it gets very stiff and is almost impossible to push down, it softens up after a little while. But it will not brake properly if i get on the brake pedal hard and quick In an emergency this could be very dangerous.. Maybe faulty ABS?

[Error404]

nope definitely the servo - BTDT. The ATF will have destroyed the seals in the hydraulic system

But as said its pretty easy to change the servo

[MrJee]

Is it the servo pump that is right next to the aux radiator? Swap the servo, new fluid and then bleed? Or are you talking about the brake servo? Sorry, i get a little confused with the hydraulic system on these cars.
I appreciate the help guys.

[Error404]

brake servo is behind the master cylinder, you push the servo push-rod when you push the brake pedal

[MrJee]

So i probably blew a seal when i did that bomb test huh?
That was real stupid of me, finally got everything squared away with this car then i had to mess something up.
Is this the part that i need?

http://www.ebay.de/itm/Audi-100-200-...item53ef84e99a