B4V Rear Brake Bleeding Procedure?

TDITim83

Veteran Member
Joined
Oct 17, 2010
Location
Ocala, FL
TDI
96 Passat Wagon TDI B4V Storm Gray 258k, 98 Jetta TDI 260k (retired for spare parts)
I am working on a friends B4V and can't seem to Get the Rear Brakes to bleed properly. Still have air inside them. Looks like a valve or something in the rear that is making the noise, maybe a Brake limiter when your slamming on the brakes. It seems to be the culprit. Is there a special tool or procedure todo this?
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
That's a load-sensitive proportioning valve. The rear should be on ramps or the suspension should otherwise be at normal ride height when bleeding so that the valve won't restrict fluid flow. DO NOT attempt to readjust the lever position on the valve. These valves are vulnerable to seizing up in one position when exposed to road salt, but that's probably not an issue for you.
 

TDITim83

Veteran Member
Joined
Oct 17, 2010
Location
Ocala, FL
TDI
96 Passat Wagon TDI B4V Storm Gray 258k, 98 Jetta TDI 260k (retired for spare parts)
If seized

will it suck air or what......This car is From PA....and has rust throughout. So wondering whats up.....We have properly bleed all the break lines and that Load sens proportioning valve keeps making noise and my peddle goes away.
 

bikeprof

Veteran Member
Joined
Sep 2, 2005
Location
Pagosa Springs, Colorado(YEAH!)
TDI
1996 Passat B4 Variant white, 1996 Town & Country 3.8 LXI
Hmmm, the B4 must have a bad proportioning valve cutting off most of the fluid to rear brakes
PB Blaster the heck out of it for a couple of days and see if that lets the valve move/adjust.

ALSO, could it be that the calipers are seized inside ?
That is another possibility, I have and would swap rear calipers to A4 ALUMINUM calipers that are VERY easy to locate and not cost as much as B4 calipers. Better and easier to work with !

I believe ROCKAUTO.COM would have parts, weird parts for our type of vehicle, try them...

Good luck !
 
Last edited:

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
If the rear load adjusting valve is bad it will ruin the bleed for the whole system. It's the one place where both circuits come together so if the valve allows air in during the bleed process it will infect everything.

I had this problem with my wagon.

As for the axle position during bleeding you can detach the valve lever and open it completely so that ramps don't matter. It's a lot easier to do this then it is to fuss with jack stands out at the rear wheels, or ramps. That way your jack stands can stay under the beam instead.

Steve
 

TDITim83

Veteran Member
Joined
Oct 17, 2010
Location
Ocala, FL
TDI
96 Passat Wagon TDI B4V Storm Gray 258k, 98 Jetta TDI 260k (retired for spare parts)
are they a direct fit?

ALSO, could it be that the calipers are seized inside ?
That is another possibility, I have and would swap rear calipers to A4 ALUMINUM calipers that are VERY easy to locate and not cost as much as B4 calipers. Better and easier to work with !



Just wondering if the A4 calipers are a direct fit? or do I have to modify? Also we have found no leaks on the brake system. Would that valve leak if it is failing?
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
ALSO, could it be that the calipers are seized inside ?
That is another possibility, I have and would swap rear calipers to A4 ALUMINUM calipers that are VERY easy to locate and not cost as much as B4 calipers. Better and easier to work with !



Just wondering if the A4 calipers are a direct fit? or do I have to modify? Also we have found no leaks on the brake system. Would that valve leak if it is failing?
There are a couple threads in this forum that deal with the MK4 rear caliper swap, also a couple posts in the "What did you do..." thread. My B3V conversion thread in the conversion forum has several posts regarding the fitment of Mk4 calipers to older cars.

Steve
 

TDITim83

Veteran Member
Joined
Oct 17, 2010
Location
Ocala, FL
TDI
96 Passat Wagon TDI B4V Storm Gray 258k, 98 Jetta TDI 260k (retired for spare parts)
So I replaced that proportioning valve and fixed the issue. No noise coming from the rear, like its sucking in air. Took a bit of purging the lines of air but after that I had a good pedal. Thanks for all the help $70 part on FCPU Euro Parts
 
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