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Old 02-28-2024, 01:24 PM   #1
MikeB
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Join Date: Jul 2000
Location: North Texas
Posts: 3,442
Re: Proportioning valve problem?

Quote:
Originally Posted by PbFut View Post
Mike, Good to see you got it working. Did you figure out the actual fail point on the valve you replaced?
No. But I did pull out the valve and spring, and another piece fell out. The only rust I see is on the threads and o-ring. There's a sleeve inside the casting that also looks OK, but not great.

The aftermarket brass valve is working OK and not leaking (yet). It came with a later model switch and pigtail that I'll use. I'm pretty disappointed that the new OE switch replacement failed so soon.

I have to make a confession here. I'm actually wondering if there was any problem at all, other that the switch being too sensitive. When I started to bleed the rear brakes yesterday, I initially had the same problem -- low flow out of the bleeder screw again. Oh, no!

But here was the problem: It's really hard to get much of a turn on a box end wrench with the bleeder's location in the wheel cylinder casting. So I was able to insert the wrench in a way to get maybe another 45 degrees on the turn, and lo and behold, fluid streamed out! Really strange because I have bled brakes dozens of times over the years w/o screwing up like this.

Oh, well. I can tell myself 1) I learned something, 2) I have new fluid end-to-end, and 3) I'll end up with a rebuilt OEM combination valve!

It was also a good day because we fixed a couple brake problems with my buddy's new-to-him 99 Silverado 1500. One of the rear caliper pistons was stuck (!) and the parking brake adjustment was too tight. No bleeding problems, though.
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Mike
1969 C10 LWB -- owned for 34 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes.
1982 C10 SWB -- sold
1981 C10 Silverado LWB -- sold, but wish I still had it!
1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming.
Retired as a factory automation products salesman.
Worked part-time over the years for an engine builder and a classic car repair shop.
Member here for 23 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!
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