2nd Gen Non-Engine/Transmission What is this "thing"?

[Nick T]

Long story short....I lifted my truck 14 years ago (3" front only) so it would fit bigger tires. The shop didn't know what this was, so my rear was not lifted. Truck sagged a little bit but I've learned to live with it, until now. I recently bought a 5th wheel and will be installing airbags when it comes in.

So, what is this used for and if I inflate my bags to keep the truck level, will this affect anything?

Thanks in advance.
P.S. I've been coming to this site for many years to get good information about my truck. Never posted anything until now. Just want to says for all you guys provide.

 

[Brian Sullivan]

Proportioning valve for rear brakes

 

[B.G. Smith]

Height sensing proportioning valve. Reduces brake fluid pressure to rear brakes when truck is not loaded, allows full pressure when fully loaded. bg

 

[Nick T]

Thanks for the prompt reply. Should I have to adjust it when I install the airbags to level my truck?

 

[B.G. Smith]

Is that block between the axle and the spring original equipment? You will have to add the same length to the rod that you lift the truck for it to work.You are gonna need all the breaking you can get with the 5th wheel. bg

 

[Nick T]

Yes, everything in the rear is OEM stock. The dealer may have added or altered something, as my sticker did mention a "camper special"

 

[WW101]

On my 98.5 I modified that a bit by welding in a turnbuckle for adjustment. I wasn't getting much brake from the rears at all. I tweaked it a bit for more rear brake and liked the improvement a lot.

 

[B.G. Smith]

The turnbuckle sounds like the way to go. If you add air bags and level the truck (raise the rear) and then hook up to the 5th wheel it's going to go back down some before the springs are seeing the load. So it's probably going to be a trial and error situation till you find the right setting. bg

 

[JR]

On my 98 I completely disconnected mine from the axle and cranked up the proportion valve to near full on. Given the mediocrity of the brakes on that truck It made them quite a bit better when the truck was empty or light loaded.
I do remember having to fool with it a bit to get the right amount of bias so they weren't locking up on wet roads.

 

[Nick T]

Interesting, this explains why I'm still on my stock brake shoe after 18 years and 120K miles. Probably on my 5th set in the front.

The turnbuckle sounds like a great idea.

 

[Joe Mc]

Nick, I hear you! about 7 years ago I converted to rear disks. since then I haven't replaced a set of front pads and only 1 set or rears. prior to conversion (about 160k miles) I replaced 5 sets of front pads and was one the 2nd from original rear shoes.

 

[Nick T]

Nick, I hear you! about 7 years ago I converted to rear disks. since then I haven't replaced a set of front pads and only 1 set or rears. prior to conversion (about 160k miles) I replaced 5 sets of front pads and was one the 2nd from original rear shoes.

I'll have to look into that conversion. I assume you got rid of the proportional valve after the conversion?
Do you still have ABS in the rear?

 

[rotohead]

You can delete the valve completely and improve the braking. There is a brake line available to replace the unit. Don't know if I still have the part # or vendor but I'll look this weekend and post if I find it.

 

[WW101]

So for what it's worth, When I was doing the tweaking on the turnbuckle to get them adjusted to my liking, there was a point where too much was too much. At least on my truck anyway. I spent the better part of an afternoon tweaking and test driving, Too much and the rears would lock up on a hard stop like what you could experience in traffic, etc. I finally found the sweet spot and overall braking was greatly improved without unwanted lock ups.

 

[Nick T]

Everyone who say the rear locks up during hard braking, after adjusting or eliminate the proportional valve; I assume you don't have rear ABS?

I'm going to try the turnbuckle metioned earlier and will post back. After finishing the airbags installation last night and leveled the truck out, I can see the valve lever was pulled down a little. I've looked into and read about the rear disc conversion with mixed results and don't think it's worth the time and money.

 

[JR]

Yes you still have anti lock, the hall effect sensor is on the ring gear. However brakes pulsing because the tires have lost traction are less efficient then tires that have not hence the need to fine tune the bias.

I'm sure the turn buckle works fine but I see no need for adjustment here. Simply disconnect from the axle side and adjust the valve until you find the happy medium. I ran this way for many years and never had the need or desire to adjust.
As far as the disc brake conversion it is pricey. I can not say if it is a worthwhile upgrade as I have never driven one with the upgrade. I always kept an eye out for a D70 or D80 with the factory discs but never had any luck. I ran the GM 1 ton wheel cylinders which were larger than the Dodge's and kept the shoes adjusted every tire rotation. Combined with the adjusted rear bias and 1 ton wheel cylinders it was a significant improvement over stock.

 

[Joe Mc]

I'll have to look into that conversion. I assume you got rid of the proportional valve after the conversion?
Do you still have ABS in the rear?

I left the proportioning gismo didn't adjust it at all. Sill have ABS and just in rear as original. The kit cost $700 and there was a bit of fab work involved as I opted for E-Brakes. Had to weld little tabs for the outer cables to land, shorten the outer cables a bit and then locate a cable end stop for the lever on the caliper. The E-Brake is not typical (inside rotor) actually the kit had calipers from a 76-78 (I think) Eldorado. Kit had caliper plates to diff, tabs for E-Brake, Tabs for hoses (I think the hoses were from a 2000 1500 Dodge front), the rotors were for a 2000 (I think) GMC 2500. Works pretty darn good IMO.
Oh, the kit came from Blackbirds Customs. Instructions were pretty decent.

 

[Joe Mc]

I too was looking for a D70 (what mine - auto trans - came with) or a D80 with rear disks but like you could never find one. I ended up with a chipped tooth on my ring gear (lost brakes and had to drive home with e-brake and downshifting - one time the trans hit 1st very firm and the rear wheels chirped, then I heard a little click from the rear - tooth chipped) and was lucky to find a whole rear from a 1st gen same 3:54s, with a L-slip diff for $300. I inspected the gears before I purchased removed rear cover and all looked good. When I got it home and inspected further it had been rebuilt at some point = had Dana ring and pinion dated 7/2009, new clutch pack, bearings and all. Talk about lucky $300 for the whole drum to drum, you'd be out more than that just for the parts to rebuild. I had to take assy out and install tone ring from my diff so speedo and RWAL would work. Also had to cut off tabs for shock mounts, the new diff didn't have sway bar so had to cut off from my old and weld on to new. It was a 7 or 8 beer job. going on 5 years now. Oh, although I couldn't locate any rear disk diffs 01.5 and up 2nd gen, every place I called wanted $1000, so $300 for my used diff and $700 for the kit same-o - same-o.

 

[Nick T]

Finally got around to chopping and welding on a turnbuckle. Took a couple tries to find the sweet spot with empty truck and will have to try again with the fiver hooked up.

Thanks for all the input.

 

[B.G. Smith]

Good looking job. Thanks for sharing. bg