2nd Gen Non-Engine/Transmission Anybody know what this is?

[JKreiss]

I've been curious for the last year or so as to what this is on the driver-side rear frame rail. I guess i'd figured it was time to ask. It's on the 99' 2500 q/c sb. I'm guessing it has something to do with the brakes as it ties in with the brake lines. It also has linkage and a bracket that connect to the axle housing. Just curious Thanks in advance for any education.



Joe <a href="http://s269.photobucket.com/albums/jj66/j_kreiss/?action=view&current=IMG_3126-1.jpg" target="_blank"></a>[/IMG]#ad

 

[kenny61]

I believe that is the valve that adjusts braking force according to the amount of weight on the rear axle

 

[ed9824v]

yes is my guess an adjustable proportional valve as stated above.

 

[JKreiss]

Thanks guys. I mean looking at it, that's exactly what it looks like but just wasn't sure if it had a name. Is that factory? I bought the truck with 60k mi.

 

[Harlacher]

I have a 99 QC and I do not have one of these. I have had the bed off a few times and I am sure I would have seen it. Was someone pulling a heavy load with the truck? Sounds like a great idea; as the load gets heavier the front brakes become less effective so transferring fluid to the rear would seem like a good idea.

 

[kenny61]

the 96's have it from factory I dont know if ABS is required or what other years it carries over too. Its purpose is to keep the rears from locking up when you have no load. the more weight in the rear the less likely it will lock up so more pressure is applied. Some members have removed it or tied it up or maybe tied it down whatever fully open is and have reprted they liked the way the truck brakes better

 

[ChrisOlson]

I have a 99 QC and I do not have one of these. I have had the bed off a few times and I am sure I would have seen it. Was someone pulling a heavy load with the truck? Sounds like a great idea; as the load gets heavier the front brakes become less effective so transferring fluid to the rear would seem like a good idea.

Harlacher..... on my 99 if i recall it is on the center attached to the Bed

but as far as a good idea, it is not, it is terrible, when I pull mine off to put a bypass hose on I will gladly send it to you if you want. Ther rear brakes with this are almost non existent. 125000 miles and have yet to change the back brake shoes and I tow a lot. 4 sets of front brake pads and 3 rotors.



have a great day

 

[Harlacher]

I will have to look again, sounds like I should have one somewhere and it sounds like it works just the opposite of what I thought it would. My back brakes hardly ever wear either. My front disk pads have been changed six times and I am on my third set of rotors. I have 200k plus. One of my front rotors is bad again, the inside pad went and I did not catch it in time. Put new pads on until I can afford a new rotor.

 

[fest3er]

The proportioning valve was the 'old' way of preventing the rear brakes from locking up. As the load in the bed increases, the bed and frame drop closer to the axle; the lever system then allows more braking power through to the rear wheels. As the bed and frame move up away from the axle, less braking power is allowed to the rear brakes. The 'new' way is to use the rear anti-lock brake system to do the job. Alas, the RWAL system is probably more flawed, since it seems to (on my '98 at least) eliminate almost all rear braking and a good bit of the front braking as well; if the RWAL kicks in, I can stand on the brake and still have only a fraction of normal braking power. Most of the trucks since the early 2000's I think have had 4-wheel anti-lock brakes standard.

 

[LVJUNIOR]

The dual rear wheel trucks did not come with the proportioning valve. You can buy a brake line for a DRW truck and replace the proportioning valve and brake lines with the DRW line

 

[GAmes]

I'm not sure what you guys are complaining about. With nearly 3/4 of a million on the clock I have yet to replace the rear shoes, and have only replaced the front pads twice. I definitely tow a lot and have no complaints about the brakes. I have rear ABS that has been unplugged for years and no proportional valve. I am not looking forward to when the rear shoes are worn out because replacing them is a lot of work on a D80.

 

[Midnite]

If you do some searches on the proportioning valve, you should find some threads where people have modified it to make it adjustable. I always thought that would be a nice way to go. Knowing that the RWAL system is garbage, it seems like bypassing the valve might make the rears prone to locking up before the fronts, but that may not be the case.

Mike

 

[Jeff Knight]

GAmes,



If your 97 is anything like my 95 4x4 the rear shoes aren't bad to change. The brake drums slide off the wheel studs. You don't have to take the axle out and deal with the hub bearings... Jeff

 

[SRath]

I have rear anti-lock on my '96 and I don't have a load proportioning valve. My old K30 does, but I disabled it when I installed Firestone Ride-Rite air bags since they work against each other.

You are better off with a manually adjustable proportioning valve, imo.

Think about it: For that device to work correctly and allow full braking force to the rear, your rear must be sagging, which automatically means you won't be braking, or steering, in a properly balanced manner anyway (with the fronts doing more of the work).

 

[JKreiss]

Well i appreciate all the input guys. I don't pull heavy with this truck, as a matter of fact, i don't really pull at all with it. Having the 04. 5, i delegate most work to it. The 99' is my commuter, grocery getter, etc. It sees little to no off-road either. I'm wondering what advantages/disadvantages there would be for bypassing it. I'm about to tackle the ABS/Brake light having been on for a year, and thought of bypassing it in the next few days while it's parked. Will removing it add risk of locking up the rears? I know if it ain't broke, don't fix it but sometimes i can't help myself:-laf

 

[Harlacher]

My brakes have always been a problem, when I first bought the truck it went back to the dealer a couple of times because of pulling to the left. Was common on the 99s. The rear brake shoes are very easy to change on mine. The ABS system is a piece of junk. My light has been coming on for months, I just changed the toner ring and I am still having problems with it coming on occasionally. The front disk do most of the work and therefore need replacing a lot. When I had my exhaust brake on it helped a lot. I towed a lot with my truck in the past and plan on doing a lot more. I bought this truck for the Cummins and have been very happy with it. If Ford would of had put a Cummins in their truck I would have bought that. Dodge did a crummy cheap job with the brakes, like they did with a lot of other components.

 

[JMcCoy]

That's my style. If it ain't broke, fix it til it is. Lol

 

[Harlacher]

JMcCoy, not quite sure what you mean with your comment. We are talking about brakes and their problems don't know what you are referring to being broke. I have over 200,000 miles on my truck and I am sure I should have changed the pads and shoes even they were not "broke" they were wore. The toner ring was worn down by the plug in my magview cover. Not broke, (it was in one piece but the teeth were gone) but it was not working anymore, the new one is. The man who said he was going to bypass the proportional valve for the ABS made it clear that his brakes were not working to his expectations. My Cummins was not broke but I have added a bunch of things to make it meet my expectations, not broke, but 500 horse power is better than 175, that broke the transmission so I had to have it fixed. We are all making modifications to these trucks to meet expectations when they are not broke. What are we fixing that does not need it?

 

[JKreiss]

I think he was referring to my comment about not being able to leave stuff alone. At any rate i'm not going to mess with that valve until i've gone through the entire brake system. For grins i took it to Dodge last summer, remitted the extortion money, just to have them tell me it's the Controller for the ABS. Funny thing was i told the Misses that before we even dropped it off. I told her they'd diagnose the most expensive part and just throw parts at it until the light went out. We used to have a good dealership, not anymore. Anyhow thanks Harlacher and everyone else a bunch for your help. I'm sorry your experience hasn't been well with these brakes, i hope i have better luck. If not, i have some black tape that'll cover that brake/abs light nicely.

 

[rivercat]

exactly what it is if you stick the brakes empty and the rear suspension unloads it stops the braking force to the rear wheels to stop a skid. You usually see these on big floaty front wheel drive cars not 3/4 ton trucks.