Brake options for a '69 GMC Diesel conversion...

[Darkrider]

Ok...since it looks like i will be hanging onto my '69 GMC C10, I need to sort out my options for brakes with this thing. It currently has the Power drum brake set up on it and i am not sure if i can make the Hydraboost booster work in place of the Vac booster. If i was going disk brakes it would be a no brainer then its just a matter of swapping the entire Hydraboost set up on M/C and all. The problem lays in the fact that the truck is a 6 lug drum brake and unless i get into expensive conversion parts or go on a search for C20 lower control arms to make a GMT400 brake set up work im stuck with going 5 lug. One option i suppose is to go 5 lug front and just live with the rear being 6 lug. Sort of like how the C3500 HDs had the wide 5 lug fronts with the 8 lug rears. Im wondering though if there is a way to just use the vac system with the 6.2 though?

 

[tanman_2006]

So is your truck currently 5 lug and you are wanting 6? or are you already mix and matched?

I guess i dont understand what your problem is.

 

[Darkrider]

So is your truck currently 5 lug and you are wanting 6? or are you already mix and matched?

I guess i dont understand what your problem is.

It is currently 6 lug. If I want to convert to disk brakes up front I will have to convert to 5 lug at the same time or have to mix and match parts to keep it 6 lug.

Sent from a padded cell in the secure ward.....trying to avoid the shock therapy...

 

[tanman_2006]

I thought Dana 44 came in 6 lug disk? Your sig says SFA swap.

 

[Darkrider]

I thought Dana 44 came in 6 lug disk? Your sig says SFA swap.

That conversion never happened. I had planned on doing a 4x4 swap but life got in the way for the most part..biggest part of it is fighting some fueling problems on my K1500. Thanks for reminding me i had that in my sig.. i will edit that out.

 

[tanman_2006]

The GMT 400 C2500 LD came in a 2wd 6lug and also the GMT800 C1500 had a 6 lug. Not sure what issues you would have mixing and amtching those parts but it might be a place to start.

 

[Burning oil]

Check out what I did to mine. Im not sure of the specific differnces in spindles, bearings, hubs....on yours, but if you can come up with a hub that fits your spindle you can then use a hubless rotor. Good chance you can machine your drum hub. Bracket spacing will be off, but when theres a will....

http://www.thetruckstop.us/forum/showthread.php?35097-Big-brake-kit-(my-way)

 

[Darkrider]

The GMT 400 C2500 LD came in a 2wd 6lug and also the GMT800 C1500 had a 6 lug. Not sure what issues you would have mixing and amtching those parts but it might be a place to start.

That is one option, There is even a how to and a parts list on the 67-72 Chevy trucks forum to go about it this way. It requires the replacement of the lower control arms with ones from a 69-87 C20 3/4 ton. and spindles for a C2500LD or 93+ C1500 (same spindle apparently that's why you didn't notice a difference when comparing spindles for your 6 lug conversion leroy) as well as replacement rotors for a C2500LD. Other then that it requires ball joints for the 88+ truck, As well as special adapters to adapt the newer outer tie rod ends to the older trucks inner tie rod ends.

Check out what I did to mine. Im not sure of the specific differnces in spindles, bearings, hubs....on yours, but if you can come up with a hub that fits your spindle you can then use a hubless rotor. Good chance you can machine your drum hub. Bracket spacing will be off, but when theres a will....

http://www.thetruckstop.us/forum/showthread.php?35097-Big-brake-kit-(my-way)

Def worth some thought for sure! If im not mistaken there is a chance that the drum may be two piece not sure on that one just yet.

One other option i have batted around a few times is taking in the trucks rear axle shafts and have them welded solid then redrilled to the 5 lug pattern and converting the front end with 5 lug parts. Ultimately all things considered i have a feeling this is the option im prob going to go for. Just do the 5 lug conversion up front as well as convert to power steering at the same time along with the hydraboost. Then after getting the truck sorted out and running eventually rebuild the rear end with a locker and have the rear axles redrilled then.

 

[Burning oil]

If your drum hubs are two piece then you might be good to go, just slap a hubless rotor on and figure out the brake brackets.

FWIW I have a 1970 K20. I converted to 4 wheel disk and Hydro boost.

 

[Darkrider]

Its actually due to this brake thing is why i was seriously considering converting the truck to 4wd. On a side note...leroy do your mfsus work on 96+ trucks? been meaning to ask you that since someone on GMT400 is having the problems that you designed that unit to stop.

 

[btfarm]

If you put a '71-'72 front setup on it, I believe they were 6 bolt discs and a direct install. As for boost, I'm not the expert on that.

Here's a '69 front pic for compare;

 

[Darkrider]

Most of the 71-72 disk brake trucks i have seen were 5 lug. I know there was a Heavy duty brake option but i think that was 5 lug as well just thicker rotors. What i think im gonna do is order up a big disk brake package from a local shop here that is 5 lug and just convert the rear axle at a later stage.

 

[Ed HD]

71-72's were 5 lug on 2WD, Mike. That's the stem of his whole problem, lol.

 

[Burning oil]

On a side note...leroy do your mfsus work on 96+ trucks? been meaning to ask you that since someone on GMT400 is having the problems that you designed that unit to stop.

Yes, 1988-2000 diesels.

Most of the 71-72 disk brake trucks i have seen were 5 lug. I know there was a Heavy duty brake option but i think that was 5 lug as well just thicker rotors. What i think im gonna do is order up a big disk brake package from a local shop here that is 5 lug and just convert the rear axle at a later stage.

I'd like to know if your drum is 2 piece? Also, in a disc vs disc I don't "think" going to 6 lug would gain much if anything. I believe the rotor dia and calipers are the same size? (I know yours is drum)

 

[Burning oil]

I made some 4WHEEL DISC emblems for the truck also.



Custom brakes, uses a Ford rear disc. (8 lug)

 

[Darkrider]

Thanks for the help guys. But sadly this project will not occur now since i had an '89 GMC K3500 offered up to me and i needed a running truck so the Dodge and the '69 GMC were traded for that truck. However i may be pulling home the '82 GMC 4x4 that the Red block motor came out of. So truck and engine may be reunited soon!