Brake proportioning valve

Joined
Apr 4, 2003
Messages
24
Saw this term on a listserve about 80 series cruisers. What is this valve? Where is it? The right front brake on my truck sometimes locks up when I have been on it too long, like in line at car pool with the kids. Dealer recently replaced the entire caliper and said it was "broken." Still have the problem occasionally. Assume dealer can't recreate the problem (so don't just tell me to take it back, I wanna know what is wrong). Thanks for any help
 
Joined
Mar 27, 2003
Messages
12,519
Location
Somewhere in the foothills...
Your LSPV is above the rear axle and adjusts pressure to the rear brakes based on the load in the rear. More load, more brake pressure.
-B-
 
Joined
Mar 14, 2003
Messages
16,100
Location
Gig Harbor WA
[quote author=Macondawg link=board=2;threadid=8896;start=msg76958#msg76958 date=1071692669]
Saw this term on a listserve about 80 series cruisers. What is this valve? Where is it? The right front brake on my truck sometimes locks up when I have been on it too long, like in line at car pool with the kids. Dealer recently replaced the entire caliper and said it was "broken." Still have the problem occasionally. Assume dealer can't recreate the problem (so don't just tell me to take it back, I wanna know what is wrong). Thanks for any help
[/quote]

whatever the real problem is it is NOT the proporting valve, it only effects the rear brakes and even if it did effect the front it would effect both sides equally. FWIW it's located on the frame, driver side up above(and a bit forward) of the rear alxe.

I dunno but when I have had a bad caliper I have always replaced both sides, I would really think a dealer would do the same, at my local dealer they rebuild the calipers in most case instead of replacing.

Not sure what really is the problem. Explain "lock up" a bit more

John H
 
Joined
Jun 16, 2003
Messages
1,802
[quote author=Macondawg link=board=2;threadid=8896;start=msg76958#msg76958 date=1071692669]
...The right front brake on my truck sometimes locks up when I have been on it too long, like in line at car pool with the kids....I wanna know what is wrong...
[/quote]

A bad flexible brake line (the rubber line leading to the caliper) can cause the problem you are reporting.

Rich
 
Joined
Jun 20, 2003
Messages
1,637
Location
Fort Langley, BC
[quote author=Rich link=board=2;threadid=8896;start=msg77221#msg77221 date=1071728096]
A bad flexible brake line (the rubber line leading to the caliper) can cause the problem you are reporting.

Rich
[/quote]

Rich - how so?

I'm just curious how the rubber line would cause this, what would be going on ?
 
Joined
Jun 16, 2003
Messages
1,802
[quote author=Riley link=board=2;threadid=8896;start=msg77225#msg77225 date=1071729805]
...I'm just curious how the rubber line would cause this, what would be going on ?


[/quote]

The inner layer of the flexible rubber line can seperate from the outer layer. Brake fluid can get inbetween the layers and force the inner layer to collapse and block off the brake line and in effect act as a one way valve. Thus you can apply the brakes, and the caliper can remain under pressure as the fluid slowly leaks back past the blockage. From the outside, all can look normal.

Rich
 
Joined
Jun 20, 2003
Messages
1,637
Location
Fort Langley, BC
Interesting Rich, I never would have guessed that could happen. Difficult one to track down I bet. I'll tuck that little tid bit away in the vault.

Riley
 

GXO

GXOR
Moderator
SILVER Star
Joined
Feb 7, 2002
Messages
11,301
Location
Woodstock, GA
Website
gxor.org
Replacing those front rubber lines from the housing to the caliper is a :banana: job unless you don't have experience bleeding...then bump it up another :banana:
 

Users who are viewing this thread

Top Bottom