no boost on brake...
Thread Starter
Advanced
Joined: Mar 2002
Posts: 60
Likes: 0
From: Sammamish, WA
no boost on brake...
I’ve been having some issues with brake boost. A while back, i took the car to a dealer and they have replaced the pressure reservoir/accumulator. All is ok but I started to see the warning light again and do lose boost time to tome totally, which really suck and not safe. This morning, I totally lost it again but I was already in the parking lot at my work.
After looking around for a while in the parking lot for other possible cause of this problem (because the car did not make that noise while building up the pressure), I found out that the unit that contains relay 66 (R66) (with 2 other relays) are not secured in the trunk area. That unit has 3 relay and R66 is for pressure accumulator. The unit in question is right next to the spare tire on passenger side and is mounted to the body with 3 points of plastic. Those were broken in my car and the unit was just dangling around with wire. You all know or heard about VW/Audi/p-car bad relays one time or another. I’m sure my relay is no exception and is wore out. But I wonder if having the unit bouncing in the car like that may have contributed to the issues I’ve been experiencing. Because the occurrence of my issue were so random, may be this unit not being secured may have been the problem. As a temp fix, I’ve shaved a towel in between the relay unit and spare tire so that the unit stay up-right without bouncing in the trunk. I did ordered the relay (R66) but they are on order (my local dealer told me it’s about $20).
Do you guys have any similar problem like this??
After looking around for a while in the parking lot for other possible cause of this problem (because the car did not make that noise while building up the pressure), I found out that the unit that contains relay 66 (R66) (with 2 other relays) are not secured in the trunk area. That unit has 3 relay and R66 is for pressure accumulator. The unit in question is right next to the spare tire on passenger side and is mounted to the body with 3 points of plastic. Those were broken in my car and the unit was just dangling around with wire. You all know or heard about VW/Audi/p-car bad relays one time or another. I’m sure my relay is no exception and is wore out. But I wonder if having the unit bouncing in the car like that may have contributed to the issues I’ve been experiencing. Because the occurrence of my issue were so random, may be this unit not being secured may have been the problem. As a temp fix, I’ve shaved a towel in between the relay unit and spare tire so that the unit stay up-right without bouncing in the trunk. I did ordered the relay (R66) but they are on order (my local dealer told me it’s about $20).
Do you guys have any similar problem like this??
Pro
Joined: Sep 2009
Posts: 662
Likes: 2
Several years ago my '95 would occasionly lose boost.
Once in say 20 brake applications the pedal would go nearly to the floor....still had adequate braking, but it was not right.
Turned out to be a check valve in the brake system, I believe located in the rear of the car; could have been an accumulator, but it was described to me as a leaking check valve.
Gordo
Once in say 20 brake applications the pedal would go nearly to the floor....still had adequate braking, but it was not right.
Turned out to be a check valve in the brake system, I believe located in the rear of the car; could have been an accumulator, but it was described to me as a leaking check valve.
Gordo
Instructor
Joined: Sep 2003
Posts: 230
Likes: 18
From: Berkshire, UK
On my previous 993 C4 the brake boost pump failed (started to leak) - the pressure warning light (the one that stays on for a few seconds after start up) began to light up intermittantly and stayed on for longer and longer. The pump was having to work more and more as pressure wasn't being maintained. Cost for a new pump was an eye watering £1,000 here in the UK (just for the part)! It's located in the space behind the front PU. Open the trunk and drop down the vertical carpet board and it's on the [your] drivers side.
