442 Restored/Rebuilt HJ code combination valve. Valve build date stamped July 24th, 1985 (5205).

[69hurstolds]

Thanks to oldsofb for his original factory combination valve. Interesting, the build date stamp on the valve is July 24th, 1985 (stamped 5205). And his car is an 87. After disassembling, taking an overnight bath in Evapo Rust, then installing the rebuild kits (sold separately...why?) for each section of the valve, I cleaned 'er up, dribbled the guts with new brake fluid and reassembled. Found a yellow paint mark on the housing right above the rear brake line outlet. It was so cruddy you couldn't see it until after I checked the part in the bath a few hours after it started to soak.

Quick buff with a soft brass brush and it looks new again. The idea is when I get to the brake line replacements, the combination valve will be a drop in and won't have to waste time redoing the existing valve. Which is also a Kelsey Hayes with code "HJ". The build sheet shows the brake valve coding as "HJ 8081" whatever the 8081 means. They sometimes put a partial part number in there along with the code, but I cannot find any reference to the 8081. Probably hit it with a light coat of Boeshield to help protect it.

If you're interested in attempting to rebuild one of these jokers, here you go with a link below. I won't bore you with the details. It wasn't as hard as it first appeared. But that tiny little e-clip holding the metering valve guts together was a little tricky. The body is cast iron, so there was a good reason they went to all brass. The corrosion could mess the cast iron ones up pretty quick. Luckily, this one seems to be in decent shape where it counted for 34+ years, although it had some corrosion present and was fairly dirty inside. The spot they placed them is pretty much a dirt trap as it is. Not sure if it would have been easier to deal with and stay cleaner if they put it up near the master cylinder like they did with F-bodies.

1979 Kelsey-Hayes Cast Iron Combination Valve Autopsy | Muscle Car Research LLC

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BEFORE:

AFTER:

The HJ code and the 5 205 stamp. The last 5 is very light. No idea what the little 12 is, unless it's the 12th hour of the day or something.

A better 5 205 is stamped on the other side:

 

[69hurstolds]

Did a little more digging and while I didn't find anything specifically on 8081, I did find another part number for an export 1984 G-body, and the part number is 18008082, which is a cast iron Bendix style ACDelco version. So I would deduce from that since the older valves started life as an 1800 part number start, the 18008081 was very likely the original factory part number and the domestic service number was 18008083. I found a reference where 18008083 was superseded to a cast iron Bendix style Delco valve 18004034, and that eventually by 25509419. Service or over the counter part numbers may change slightly from factory production use, so maybe that's why 8081 wasn't listed in a parts listing. Up until recently I used to think the 25509419 was the original p/n for 1985 and a Bendix style unit, but turns out it was the ultimate superseded p/n as everything started swapping over to the brass units. Oh, that's not counting all the "interchangeable" part numbers. Good God.

Here's the valve I got that was supposedly the latest number 25509419. Turns out it wasn't quite and is actually an 18004034. And that tag under the button doesn't have anything printed on it. Still a proper substitute, but still. If the rebuilt Kelsey valve doesn't work, I'll get some more kits, and rebuild the one that's on there. If THAT doesn't work, then my backup to the backup will be this one. And if all of that fails...I also have a new 25509419 brass unit. So I'm betting I'll be covered with all GM parts somehow.

All this supersession sh*t makes my head spin sometimes.

 

[69hurstolds]

I know it's hard to decipher, but the area circled is the valve code and I'm guessing the last section of the production part number. This is the build sheet, or what's left of it, from my old gray 85 442. Intersting, next to the brake valve is the master cylinder code. Since the gray one was KL and the white one is DK, they changed the code for the M/C. Same with the fan clutch it appears. The "fan assembly is 036, with the p/n being 22511036 since it was the p/n for the HD cooling fan, the gray clutch was coded "OJ", and the white one is "OL". Both cars had the V08 RPO for HD cooling.

And a white one...

 

[pagrunt]

I know it's hard to decipher, but the area circled is the valve code and I'm guessing the last section of the production part number. This is the build sheet, or what's left of it, from my old gray 85 442. Intersting, next to the brake valve is the master cylinder code. Since the gray one was KL and the white one is DK, they changed the code for the M/C. Same with the fan clutch it appears. The "fan assembly is 036, with the p/n being 22511036 since it was the p/n for the HD cooling fan, the gray clutch was coded "OJ", and the white one is "OL". Both cars had the V08 RPO for HD cooling.

View attachment 145492

And a white one...

View attachment 145493

I just checked out my '81 Monte's build sheet just to see what code was used on mine & it's was a HJ valve.

 

[Olds G's]

Checked out our 84 Cutlass Brougham build sheet and it shows the HJ valve as well. I have the original valve but just recently swapped out with a new

brass unit. I'll follow your lead 69hurstolds and rebuild the original.

 

[oldsofb]

Thanks to @oldsofb for his original factory combination valve.

Glad to help. It's like my 442 donated a kidney to a brother. Glad it went to a good home. 😀

Hutch

 

[69hurstolds]

Looked under the 85 and 87 out in the shop tonight, and they both still have their tags on the front of the metering valve.

Poking around the internet, seemed like the HJ 8081 was a common valve for the G-body regardless of make.