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Combination Valve

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1995 12V 2WD. Having all kinds of probs with the brakes. Rebuilt / replaced..EVERYTHING.. except combination (proportioning), valve, RWAL valve and rear dif speed sensor.. Oh.. and the Brain box under the dash for the ABS. I read there's probs getting all the air out, but I don't think that's the prob. I found the little 'button' under the electrical connector of the comb valve, stuck and I'm not sure it's moving freely, but that's just an indicator, (Right?). Has anyone taken this combination valve apart to see if it's sticking, etc.? Can't get a new one and even the junk yards don't have any 2nd gen diesels for parts.. This could be a huge problem. I do not have the ABS system with the 'pump'. This is it.
2022-09-28 Dodge master cyl (1).JPG
 
Sorry, still new at this a bit.. The pedal goes almost to the floor, and the last 1 1/2" the pedal gets harder and begins to feel almost 'normal.. but on gravel, the rears are locking up quickly. I still can't tell if the fronts bare working, but the rears will lock up.
A little deeper history.. years ago after an incident crossing some RR track in the rain, the RWAL system almost got me into a rear-ender, so I disconnected the 'system' by pulling the 20A fuse and removing the dash bulbs for 'Brake', and 'ABS'.. I recently, after the 1st brake job, (a year ago), put everything back to stock config., and the brakes felt 'normal' but the RWAL system was not working, (w/ BRAKE and ABS lights on), and rears would lock up 'early', and then to complicate things, in short order, the front end would shake like crazy after about 10 miles and would get worse. As the brakes (front) would heat up even further). As the months rolled by, that problem would 'lessen' slightly, but would still get bad after several miles and moderate brake use. That turned out to be a right front (cheap) caliper was sticking badly, (and the left front also but not completely), and cooking the brakes, so I did a complete brake job again, including (another) master cyl, booster, rotors, [better] calipers, pads, rear drums, rear shoes AND installed 1 ton rear wheel cyls. Now, after this 2nd brake job, the pedal was going almost to the floor before beginning to act 'normal', and it seems like I could not get all the air out of the system. (At least that's what it felt like).. Bled these brakes many times.. no luck. (I had read that is is difficult to get all the air out of the combination valve and / or the RWAL valve..?).
I think ?? the combination valve is stuck, but I'm also not dissuaded from thinking there is STILL air trapped somewhere.. I don't know, and, of course, you can't get a new valve, (or a used one, for that matter), anywhere.
Sorry for the long discription.. but I'd appreciate any suggestions.. and I'd really like to know if anyone has tried to take one apart?..
 
I just spent 20 + minutes writing 3 paragraphs of explanation, and realizing I needed one more point to add, I tried to 'add' another, 2nd post, and the system killed my 3 paragraphs.. This ism why I hate computers
 
AFTER I had posted the the 3 paragraphs.. It got wiped out anyway. How the H*** does THAT happen? I can't believe this is happening.. in the middle of THAT last post the' system' jumped to a new, blank post page, and then .. warning pop-up, says I have to wait "at least 18 seconds before performing the requested action".. WTF?
I'll come back and try to start over when my blood pressure goes back down.
 
Yes, thanks.. the rear shoes are adjusted correctly. (I've done dozens of brake jobs and never had this kind of trouble before). The brake lines from the wheel cyls up to the engine bay are free of air. Also the new master cyl was bench bled properly. I thoroughly believe it's either air in the Combination valve, or it's stuck inside. The RWAL valve never gets the chance to 'activate' as the rear brakes still lock up first. I really really want to know if anyone has had the combination valve apart, and what they found?.. Thanks
JG
 
Yes, thanks.. the rear shoes are adjusted correctly. (I've done dozens of brake jobs and never had this kind of trouble before). The brake lines from the wheel cyls up to the engine bay are free of air. Also the new master cyl was bench bled properly. I thoroughly believe it's either air in the Combination valve, or it's stuck inside. The RWAL valve never gets the chance to 'activate' as the rear brakes still lock up first. I really really want to know if anyone has had the combination valve apart, and what they found?.. Thanks
JG
I think Ozymandias has your problem figured out. The links he provided are worth your time. While my family was watching Bob's Burgers, I did a little lookin' around the interwebs.

All is not lost, even if your current proportioning valve is beyond hope. Speed shops (Summit Racing, Speedway, etc) sell adjustable PVs that you can set up yourself. My preference is always the OEM, unless I have (for example) retrofit a drum/drum car to disc/disc. The brakes on our first-half Gen 2 trucks are essentially GM/Delco. Most parts availability tracks what's available for Chevy brakes, which is why the 1 ton rear cylinder conversion is so easy to source. I did it years ago.

This ebay seller advertises a whole bunch of aftermarket PVs. A call to them might get you a new one. https://www.ebay.com/itm/2841076086...e+Products+CPP&_trksid=p3458402.c101506.m1851

I don't know anything about them except that they came up on a duck duck go search for proportioning valves.
 
Thank you very much. There's a lot of info there but all helpful.. It wouldn't surprise me if there was more than one prob at the same time. I'll read all this until my eyes bleed ..lol.. Since you seem to know a good deal about this..I found a universal proportioning valve that, with a little customization of the mounting, and some new brake lines, it looks like it will fit reasonably. It was, apparently used in Mopar..Jeep.. although this doesn't fix my RWAL valve prob, at least this valve would be new. Any comment?.. would this being made for a different, (ie: lighter) vehicle be any problem on the Dodge Ram 2500?
2023-09-19 PV2 01.jpg


2023-09-19 PV2 04.jpg
 
Should be OK, with emphasis on the word should. Contacting the seller is worth your time.

Edit: That looks identical to universal-type PVs I'm seeing onlinine. For what it's worth, it seems that some PVs have wider application than I had thought. This expensive ebay listing applies to more than 2,000 vehicles, including Delco brake models in the year & weight range of our trucks. And also MoPars, Jeeps, & passenger cars. Didn't see any golf cart listings. :D
https://www.ebay.com/itm/2738272579...nIvQ9mDnBVoKs3NrI6eGL5Mw==|tkp:Bk9SR6qXnJzZYg
 
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I'd would also look for -non- dodge proportining valves, they look pretty generic like many parts in our trucks are. So you might can find a part that fits like a glove from Chevy or Ford where it is still available. Very much like the hydroboost units that are more or less interchangeable between the brands.

For example found the PV for the 1995 Dodge Ram VAN 2500 available and looking very similar.
Same for Ram 2500 from 1998 which also looks the same as yours.
 
I also just learned about the PV Valve 'Bleeder tool', a little screw in thing that holds the valve centered when bleeding.. Apparently this is a well kept secret. I have the 1754 page factory service manual, and it say bupkus about it.. I also found a PV valve that looks like s direct replacement, including the little slot in the botom to fit the Dodge bracket, and this one comes w' the 'tool' and elsewere I found the little wiring connector that fits.
 
Unlikely this is still happening but I remember reading here of a few members getting the front callipers in the wrong boxes, left in right and right in left. Make sure the bleeders are at the top.
 
That's what I thought. The other generic PV's I found, are mechanically the same, but physically they have a 'rear facing' outlet for the rear brake line and it won't work on the Dodge ram without moving the mounting position at least 1" farther forward, (the 'rear end' of these PV's is only about an 1" from the booster in the Dodge, leaving no room for the brake line to exit), and, unfortunately, shifting the PV forward 1", (or more), would require at leas 2- 3 new brake lines connecting between the PV and the RWAL valve, etc... and I couldn't find anyone to even consider making those types of very short, very tight bends in brake lines.. So there's that problem also. This one, (prior pic), will fit physically.. down to the little rectangular tab, slot, where the bracket attaches. So, for that, I'm ecstatic... AND it gives me more confidence to tear into my existing proportioning valve and see if it, (they), are repairable. In that vein, In my searching, I came across a video but a guy who says he thinks he's the only guy that can repair these things. I'll try to see if he still exists. Might be interesting.
The other most important piece of info was discovering the need to use that little 'tool' to hold the PV valve, (shuttle valve inside), in it's center while bleeding the system, and that's a HUGE bit of news.. (Google proportioning valve bleeder tool). ($7 to $15).
These type of proportioning valves were only used for about 1988 up to maybe 1998, so this bleeding problem information has been lost.. like a lot of other info. Still, for it NOT to be in the factory manual is unforgivable.
 
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