Checking my brake pads this week ,I find that the REARS are worn TWICE as much as the FRONTS & I know this is not normal(see previous posts ).On the rears all pads are otherwise evenly worn & the same is for the front pads. I used the PBR pads from IPD in both F&R calipers. I also noticed that the F&R Caliper seals are toast. Cars has 160K+ miles so I am thinking replace or rebuild (which is better ? ,I lean more toward replace).
My info also tells me that there could be a problem with the Brake Force Distribution Valves (BFDV's).I assume these are expensive (Volvo parts = Mucho $$$$$ in most cases). Are they easy to replace ? I am very handy (replaced the blower motor according to book & works great).
I would prefer to replace or rebuild the F&R calipers first & then see what happens before replacing the BFDV's.
Although I use Castrol LMH DOT 4 brake fluid I confess to not flushing the brake system as often as I should (Last time was in spring 2001)

That item is, I think, subject to mis-naming. Let us be certain that what you say and what I think you say are the same, OK?

There is a junction block located in the front, low, and at the bottom terminus of the two lines from the master cylinder. It has two lines in, six lines out, and an electrical connection. It is sometimes considered a distribution block. Its usual mode of failure is leaking.

There are proportioning valves in the lines to the rear brakes. There are located in each line somewhere before the lines reach the rear axle area. Like any other part, they can fail. I have not experienced such a failure.

Which of these two items are you referencing with BFDV ?

Regards,

Bob

:>)

The first item you referred too is the Brake Line Junction Block as illustrated in the new IPD spring catalogue top of page # 23. part # CX1273052. That is not what I referred to.
What I referred to are the Proportioning Valves.On p. #19 of the IPD catalogue at the bottom of the page they are referred to as Brake Force Distribution Valves- BFDV. It is this I referred to.
In the blue Bentley manual In section 520/Brake Hydraulic System they are referred to on the left illustration on p. 520-3 as the Rear Wheel Brake Pressure Regulating Valves. This is what I referred too.I beleive they are one & the same.
Hope this clears up the confusion.

Good that most of us have the IPD catalog. Pictures are always helpful.

The problem that caused my post is one of standard nomenclature. Sometimes there seems to be none. For example, my old Volvo Service Manual, 240, Brakes, names the Brake Line Junction Block as the Pressure Differential Warning Valve.

It also names the Rear Wheel Pressure Regulating Valve as just about the same thing - regulating valve.

BTW, it does have instructions for replacing those regulating valves. Basically its clean area, remove old ones, install new ones, bleed system.

Thanks and Good Luck,

Bob

:>)

OK great ! but my question still is should I replace/rebuild the calipers first & see what happens & if there is no change then replace the Rear BFVD 's ?