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I am new to the club but did search Techinfo for anything on my issue before posting.

I need to replace both rear proportioning valves (GM/ACD# 19244448). I just received them from GMPARTSGIANT and they look are different than what came off. My question/concern is what type of flare (ISO or bubble) do I need to use inside each end of the valve?

I do not have the old ones that I can check (hind sight is 20/20 ) and when looking down inside it almost seems as if a bubble flare but the rest of them are ISO (see pics).

The second question is which what do they install? I assume the arrow (see pics) is to point from the front toward the back of the car. This would mean the smaller of the two holes (see pics) is toward the back of the car which makes since it is supposed to reduce the pressure going to the rear brakes.

Feedback is appreciated. Okay, seems I can not attach pics???

I believe everything is bubble. I've replaced mine, but can't remember which way they go... search my name and prop valve. I know I've said here somewhere.

When I did mine, I used ISO to bubble adapters since the bubble flare tool was expensive.

Here's how to post pics:
viewtopic.php?f=9&t=146

Bubble. Get some ISO to bubble flared metric-threaded 3/64" brake line. Put the bubble flares into the valves, and the ISO flares to each other.

BTW, there's an excellent Pull-a-Part down in Columbia on Monticello Rd.. Lots of early-90's H-bodies there, or at least there were ~9 months ago. The brake lines on my LeSabre all came off a car in that yard, back when I lived in Columbia.

LeSabre in Buffalo wrote:Bubble. Get some ISO to bubble flared metric-threaded 3/64" brake line. Put the bubble flares into the valves, and the ISO flares to each other.

BTW, there's an excellent Pull-a-Part down in Columbia on Monticello Rd.. Lots of early-90's H-bodies there, or at least there were ~9 months ago. The brake lines on my LeSabre all came off a car in that yard, back when I lived in Columbia.

Thanks, I will check out the pull a part. I ordered a flaring tool that will let me do bubble as I expect to be re-doing a lot of the lines on this car as the next weekest link is exposed.

Don't bother doing bubble flares. Buy a roll of brake line, form what you need, then get smaller premade sections with the metric ISO flare on one end, and the bubble flare on the other. Then a bunch of ISO to ISO connectors and fittings. Run the lines in sections, and put in the bubble flares only where you absolutely need to, such as to the rubber hoses, ABS pump, proportioning valves, and wheel cylinders. You might spend more, and go less insane trying to make a bubble flare.

Also, get some tubing bending pliers. The little "tubing benders" sold at parts stores for $5 are not worth your time or money. They're fine for replacing one line, not a car's worth. The angles possible with those won't match some of the turns down there.

The easiest way is to yank the lines off a car in the yard, and swap them directly. That's what I did. It is entirely doable, especially the back lines. Plus, the yards often overlook the proportioning valves since they're a part of the line. So it's about $20 or so for the entire car's worth of lines that are already pre-formed and have the right connections. Being where you are, rust ought not to be too big an issue.

And, the metric flare-nut/line wrenches from Harbor Freight work just fine.

Good luck!