spring brake conversion should i

[Utahclaimjumper]

George, as soon as I get back this week end from a trip I'll look for the pot numbers, by cutting in half I mean I used an abrasive saw and cut them cross wise, then useing a 1/2 inch thick by 3 cold rolled tab I off set them to line up with the newly mounted pot push rods and clevises, welded them up with low hydrogen rod for strength. They have been working great for ten years, I found several years later that the offsets were available across the counter.>>>Dan

[4106-123]

dan did you also have to relocate the pot mounts?

[pvcces]

We had our spring brakes installed by Southern Oregon Diesel about six years ago. I don't know if they will do the alteration anymore.

The mounting pads for the original cans were cut off of the air beams and the air beams notched just enough to allow remounting of the pads; they got one of them 1 1/2" and the other one 1 3/4" closer to the axle. Both cans use the original slack adjusters and either one can be removed from it's mount without disassembly of the can.

This left an inch or so of clearance between the cans and the bulkhead. They have always worked perfectly.

It's important to get the mount strong enough; 30 inches times 125 psi is a bit less than two tons of force, so the welding needs to be able to handle a suitable safety factor. I think that 6 to 1 is a good target, so make the bracket weld capable of standing 12 tons of force.

Also, be sure to get the air supply from the brake side of the system, not the auxiliary side. The brakes have to be able to work with an air line ripped off of the suspension, etc.

For what it's worth.

Tom Caffrey

[Barn Owl]

I like mine. It is a tight fit.

[4106-123]

barn owl did you have to relocate the mounts?

[Dallas]

I like Relocating to Spring Break!

Maybe I'll go with BK this year!

(Can I Bryce, Can I? hunh, Please, Please, Please?)

[PADoug]

Dallas Dallas Dallas..We're talked about Buses, not getting BUSTED. 
Besides, from what I hear, you are the "Cat's" meow anyway.  Wish I had a woman like that. (Does Cat have a sister, say in the 20-40 range? I have family down in TN, so a "visit" might be in order...LOL) Tell ya what; I'll apply for BK's "School of Instruction" about Spring Break and maybe learn a thing or two about "DD3's" while I'm at it.

By the way, I thought spring brakes were standard on most of the GMC's. I was considering a 4905 several years ago (before I became poor). I guess I didn't know what I was looking at. (Now that I've joined the boards, I'm learning so much more).

Doug

[Barn Owl]

barn owl did you have to relocate the mounts?

PO had the mod done. I wish I could be of more help. I like them and think it would be worth the trouble to make the changeover. Whoever did the work did a good job. I cannot tell there was a mount change if there was one. I will look closer the next time I am under it.

Laryn

[Barn Owl]

Dallas,

I know what two of the three got for a graduation present!..

[JACKRABBIT4106]

For those of you that have switched to spring brakes did you also install a SR1 valve and a DC4 valve and where did you mount the extra air tank? Barn owl could I get you to take a pic from bottom up or top down?
Erik

[Barn Owl]

Erik,

I will take as many pics as you need. If it's not raining I will get up under it this weekend. Let me know what you are looking for.

Laryn

[4106-123]

I WOuld also like to know how the air is routed as compared to the original system? were does the button on the dash lines go ect? thanks george

[JACKRABBIT4106]

I am looking for where the brake pot mount is welded to the suspension. Are the chambers 30/30?
Thanks Erik

[Barn Owl]

  I didn't forget about you guys. Went out for some Christmas shopping and as always it took longer than planned. I will be under the bus soon because I am replacing the Sheppard steering box and the pump. My father is picking them up from NIMCO next week for me.

[Len Silva]

Nearly everything you need to know is here:
http://www.bendixvrc.com/itemDisplay.asp?documentID=4631

Len