Braking Woes, LSPV, MC, DS Rear issue (1 Viewer)

Joined
Mar 22, 2010
Messages
231
Location
Orem UTAH
A little history to start. YES, I have read every brake bleed and LSPV thread I could find.

When I bought my 80 about a year ago, The brakes were spongy. Found that the MC was recirculating fluid and was bad. I replaced the MC and bled it properly, about 8 times through the system both manually and with a vacuum bleeder. Brakes better but still a bit spongy.

Worked on determining why I was spongy and discovered the DS rear caliper was seized/ineffective. replaced it and lots more bleeding. Better, but still spongy.

A few things that I worry about. "HISS" when holding brakes at start-up...possible leak from booster? The Vacuum line from the booster to the engine is fine, have checked it repeatedly. The hiss seems to come from the area of the brake pedal, Unable determine source.

Recently took the truck in for State Inspection. They conduct a Skid test here. DS brake application failed. the other 3 are working great.

When I run through bleed again, I get very little fluid flow at the DS rear caliper. I take the line off at the caliper entrance and get better flow, but it's a new caliper with new fluid and lots and lots and lots of bleeding.

Is there a reason why the LSPV would not transfer some brake pressure to the DS, but is doing fine to the PS?.

I am not yet lifted and have not played with the BPV or LSPV other than to bleed the LSPV.

Suggestions would be helpful. Have read every post I could find and not sure what my solution is going to be. Have 2 weeks to pass re-test.
 
Joined
Dec 10, 2007
Messages
7,259
 
 
Maybe the replacement caliper is defective or you could have bad hard or soft brake lines to that wheel?? I found (after going through two quarts of brake fluid) that you have to follow the bleeding procedure exactly to get all the air out.
 
Last edited:
Joined
Mar 22, 2010
Messages
231
Location
Orem UTAH
Tore into it again today and found that there was diff oil on the rear pad... has to be outer axle seal.. picked one up and cleaned everything out... retest and passed. But only barely. I ought to replace the pads that were saturated in diff oil.
 

jvazquez53

El Tractor
Joined
May 6, 2007
Messages
3,399
Location
San Juan Puerto Rico
 
 
Tore into it again today and found that there was diff oil on the rear pad... has to be outer axle seal.. picked one up and cleaned everything out... retest and passed. But only barely. I ought to replace the pads that were saturated in diff oil.
Need to replace that axle seal, on bleeding, I bled mine to the point that clean fresh brake fluid was coming out. I used a cheap bleeder ($8.00) that works, you have to be patient. Don't forget to bleed the LSPV last.
bleeder.jpg
 

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