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Project Rear Disc Brakes

SmithvilleD

Active Member
Messages
910
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123
Location
St Joseph, MO
#61
That part # shows up as fitting the C3500HD, disc/disc P30 chassis vehicles, & one specific subset of Tahoes & Cadillacs. Finding one will be the trick. Might be in someone's new old stock inventory, or have to find in a boneyard.
 

THEFERMANATOR

FRANKENBURBAN
Staff member
Lead Moderator
Messages
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2,765
Location
ZEPHYRHILLS FL
Staff #63
I know where theres one at, but don't know when I'll be back down that way. I checked, and the police TAHOES got 2500 brakes on them is all. They got the 11" rear drums with 1" wheel cylinders, and the mid sized single piston calipers.
 
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13,305
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3,533
Location
alaska
#64
Information
This is a valve kit for Chevrolet, Chevrolet Trucks, Cadillac Trucks and GMC Trucks cars. This valve kit fits 27 General Motors car models which have been manufactured for US market since 1966 till 2007. This part is genuine General Motors part with GM OEM part number 12548278 and belongs to group #04.690.

Valve kit dimensions are 3.30 in × 8.30 in × 5.00 in. Whole package with valve kit weighs 1.14 pounds.

This valve kit has manufacturer's warranty and 100% fits for General Motors cars. Valve kit is made of top quality materials, it passed not only all manufacturer's tests but also General Motors quality control and, has to endure rough road conditions over a long time.

In spite of higher price of genuine parts buying GM genuine valve kit will be a smart decision, because you will be absolutely sure that GM genuine valve kit will serve you longer and will provide maximum safety and performance.

Brake combination (code l) (includes valve, connect) (acdelco #172-2243)
 

Big T

Well-Known Member
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Location
Fullerton, CA
Thread starter #66
http://www.wholesalegmpartsonline.c...g-Valve-VALVE-VALVE-KIT/2663071/12548278.html

Quick search. Maybe better pricing elsewhere?

For used I would do a parts locator search on p30s, problem is - did some mechanic swap it for something before.
Thanks!

So this weekend is the periodic 40% off sale at the Pick a Park boneyard circuit in SoCal. At 40% off, I should be able to pull as complete GMT 800 axle assembly for $200 and they weigh close to 400 lbs. Then I get the pleasure of buying a proportioning valve for nearly $200 and the shipping weight is 1.14 lbs. I'm glad they don't price the axle by weight.

A quick check of inventory shows at least 4 different GMT 800 2500 HD trucks have gone into inventory in the past 2 weeks at different yards, many within 15 miles of me. SoCal with its 23 million people and congested freeways, makes for fertile hunting grounds.
 

SmithvilleD

Active Member
Messages
910
Likes
123
Location
St Joseph, MO
#68
If one finds a possible donor in a salvage yard & the axles were gone, the RPO code associated with disc/disc is JF9.

I have messages in to a few dealers to confirm they actually have stock. Lots show a listing for this part number but have no inventory.
 

SmithvilleD

Active Member
Messages
910
Likes
123
Location
St Joseph, MO
#70
I'm also sorting out mating the parking brake cables. I have regular cab/longbed GMT800 rear right & left cables (the cables off each brake may be a standard length & all the different body configurations get adjusted in the intermediate cable?

Either way, I'm wondering if anybody might have easy access to a GMT800 to get a picture of the pbrake equalizer setup? The one's I've found so far use cable ends similar to stock GMT400 with one of the rear cables ending in threaded rod (the other side terminating in a barrel plug). And these two come together in the equalizer. The cables I have both terminate with barrel plugs.

20160321_124722.jpg
 

SmithvilleD

Active Member
Messages
910
Likes
123
Location
St Joseph, MO
#71
Messages from a couple dealers summarized: Part out of production & not showing anywhere in the dealer network.

If I can find a used disc/disc combination valve, I want to pull the spring that sets the knee point of proportioning to rear brakes, & compare it to some springs from the old/more common style GM disc/disc proportioner springs.

Want to compare/contrast the metering & proportioning sections.

It might be that the newer combi valve block that fits on the GMT400's EBC310 abs, uses the same spring/valve components as the older, more common style combination valves?
 
Last edited:

EppNation

New Member
Messages
16
Likes
1
Location
Tampa, FL
#72
Any more progress on this fellas? Some of these parts have become available to me which has me doing the research... You guys know your shit! I'm impressed with the knowledge and level of detail you have gone into.

Big T, major kudos on taking incremental steps to confirm/correct compatibility as you go. Whenever I have any part of my burb opened up the "well, while I'm in here, may as well ______ ___________ _________" attitude takes over.
What's condoned it recently was always haveing a work truck available to bring me home and back...and to all the parts stores...and bone yards... and more parts stores. Haha.
Used to be that I didn't have a vehicle until I had it back to driveable. Definitely shortened the list of ongoing projects lol
 

Big T

Well-Known Member
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Location
Fullerton, CA
Thread starter #73
Both SmithvilleD and I have been distracted by other life issues. I believe SmithvilleD got his axle swapped (see attached pic), while we currently have the axle out with a friend to have the spring perches welded on. When not distracted by work, or end of life matters with my mother, I have been working on reaming the GMT 800 steering knuckles to fit both my son's '94 and my '99 Suburbans. Those are now done and ready to install. I need a clear weekend to do mine on the '99 and that will include replacing bushings on the lower A-arms.

As noted, dealing with end of life issue with my mother who has terminal ovarian cancer. We have about a month left with her.
 

Attachments

Big T

Well-Known Member
Messages
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Location
Fullerton, CA
Thread starter #77
Thanks guys.

Hospice care said less than a month and that was earlier this week. Her condition is deteriorating quickly. We have round the clock care in place to make her comfortable. We brought the grandchildren (2 1/2 and 4 weeks) to visit today. They have no idea what to think, but my mother appreciated it.

It's sad. Nothing we can do but make her comfortable and tell her we love her. She's a shadow of her former self. She was a tennis player, self taught, who became a Conference Champion while at Penn St. It's sad to see the cancer basically consume her once athletic warrior body.
 

WarWagon

Well it hits on 7 of 8...
Messages
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3,277
Location
AZ
#79
Sorry to hear that. Visiting and the grand-kids doing so is the best thing you can do regardless of the "bad mood" pain and pain killers put one in. It's a break from the non-stop pain and cheer that someone still cares.
 

Big T

Well-Known Member
Messages
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Location
Fullerton, CA
Thread starter #80
Time to catch up. My mother passed about 12:30 am on 12/7. I myself was laid up in bed with a back spasm so severe it sent me to the ER and I have never been to an ER except to take my son when he broken his arm. I was working in the yard and around the home on the 4th getting ready for anticipated post funeral reception. Repeated bending over sent the back into severe spasm. They ended up shooting me up with 2 mg of Dilaudid, which is a morphine ketone. It was the same stuff they were using on my mother to control the pain at the end. I got the call at 12:38 on the 7th that she had passed. My sisters were with her. I cried myself back to sleep. It sucks. I won't get to talk to her anymore.
 
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