The Stovebolt Site Forums The Shop Area Engine Shop CPP Disc Brakes .. Problem?

I attempted to install my booster on my 52 3100. I have the kit for 47-54 from CPP. I have read the other posts on how others have run into the brackets not being straight, but I cannot figure out how to mount this kit without removing the frame crossmember that holds transmission.

Has anyone used this kit...did you remove or modify the crossmember.

Also did you have to get different brake lines?

I thought this kit was a direct bolt up but I am not getting a good feeling.

What transmission do you have in this truck? A '52 3100 did not come stock with a transmission crossmember. The stock arrangement has all the brake pedal stuff behind the crossmember the bellhousing bolts to.

I have pictures on my web site showing the problems I ran into with the CPP kit. Click on "Front suspension".

I had to do some cutting and welding and bending to get it to fit. I did not have to remove or modify the crossmember for the brakes. (I had to modify it for the auto-trans.)

Yes you will have to re-plumb your brake lines.

I'm in the final throws of problems with my formerly frame mounted CPP "bolt in" master and booster. I had a 7" booster/master on a disc/disc set-up on my '49 Suburban. The booster was too small for the application...I had to go to an 8" double diaphram booster, and it wouldn't fit, also because of the tranny mount. I had to move everything and go to a firewall mount with a new drop-down pedal assembly.
The inital set-up just couldn't get done for a 4 wheel disc application( barely an acceptable pedal)on a 4200 lb truck...even with residual valves(2).

My '52 came with the three speed tranmission and it has not been touched so I'm am sure it came with this crossmember.

I ordered this disc brake kit from Chevy Duty their description was just a cut-out section of the actual description from the orginal manufacturer CPP. I went to the CPP's website and they mention that in some cases you must replace the crossmember with one that they offer.

This is a whole other topic but Chevy Duty charged $150 more than the same kit from CPP. :mad:

I'm still trying to understand the problem.

I looked at Charlie's pictures, is this what yours looks like? Is the problem with the crossmember itself? I still don't understand how a crossmember that should be in front of the transmission is in the way of a booster that should be beside the transmission.

No, mine doesn't look like his. I have a cross member that fits basically across the frame rails at the base of the transmission. It sits under the point where the transmission and the torque tube meet. I have pic's if you want me to send them to you.

Apparently not all trucks have these.

A cross member at the rear of the transmission is normal on half ton trucks. I have them on my 49 and 53 and on a 51 I am rebuilding for someone. The bottom two bolts of the ball housing collar bolt to the trans mount which in turn bolts to that cross member.

I've just looked at three of my half tons and not one of them have a crossmember in that location. Mine are '52, '54 and '55 1st. Did they change the location at some point?

I have recently bought the CCP kit with the power booster and it is not going to fit with the cross member on my 49 half ton. The CCP "tech" suggested to make the cross member out and didn't think it was original. I'm not really happy with this answer as the cross member is substantial piece of the frame and supports the rear of the trany. He didn't think the after market would work with the 3 speed oringinal trany. I guess I'm not happy with the "bolt in, will fit in the original location" advertizing. Is there any solution to keeping the power booster?

My truck (original 4 speed) has the crossmember. Well, my garage has the crossmember. I took it out to replace the rear transmission mount rubber (it bolts in) and never put it back in because the new mount didn't quite fit. I haven't noticed any differance with or without it. I suppose it adds some strength to the drivetrain where the U-joint housing has the potential to be tweaked by the torque tube moving around when hitting bumps but I have had some heavy loads in the truck on bumpy roads and the shift lever doesn't move around much and the motor mounts seem stable. Since it seems to have been discontinued later I think you are probably ok to remove it.

The chev parts book lists a trans crossmember up till 53.

Even with the after market cross member sold by CPP it will be a really tight fit.

I haven't mounted everything up yet but from just holding everything in place I will have to modify the new cross member from CPP to work with the power booster. I am thinking from the comments that I am not going put in any cross member in.

If you have more length to play with and you can't quite fit the booster because of the diameter - consider a Hydroboost. It runs off the power steering pump instead of engine vacuum. It is quite a bit more compact diameter-wise, and can supply more than enough power to operate 4 wheel disc brakes.

You could also use a remote mount brake master cylinder and booster by using the stock master cylinder to operate a slave cylinder. The slave cylinder would operate the remote mount brake system.

In the Chevrolet Shop Manual in the Chassis section, page 0-8 shows a drawing of the half ton chassis with the crossmember. Further on in the book under Transmission removal it refers to the crossmember when undoing the trans mount bolts. All of the parts suppliers sell either complete trans mounts or kits to repair them. These trans mounts bolt to that crossmember.

I bought CPPs kit to convert my front drums to discs. I specifically asked if their kits with the master cylinder in the original location would interfere with the stock crossmember. I was told plainly that yes, the booster will not fit. Their manual conversion kits, without a booster, will fit fine. I asked here, and a couple of folks said they run manual discs on their 1/2 tons, and they stop fine. No problem.

But the overdrive automatic I plan on putting in will also interfere with that crossmember, I think. Is it safe to remove the old crossmember completely, if I'm putting in one of the tubular trans mounts? Then I'd be clear to use both power brakes AND my O/D trans.

Thanks,
mark.
'51 KY 3100

I've gone and looked again at each of my trucks, and not one has this crossmember. But as I've pointed out to others on other questions, you can not assume a 50-year-old truck has not been modified.

Apparently that crossmember has been removed from every pre '54 1/2-ton I've owned.

Today I have a '52 GMC Sububan, and a '53 GMC 1/2-ton panel that do not have the crossmember.

My other pre-'54 trucks are all bigger than 1/2-ton and apparently didn't have it?

So here is the conclusion I'm going to stick to. Not one of the eight AD trucks sitting in my yard today has a transmission crossmemer. Not one. Beyond that I can't prove anything.

UPDATE -- Still no response from CPP about the MISSING PARTS from the disc brake kit I purchased from them. Two emails over the last six days....

Will post again if they respond, or if they don't...

UPDATE 10/31/05 -- Got a phone call back from Randy in response to my emails the other day; and my missing parts arrived in today's mail. CPP made it right!

Cheers,
mark.
'51 KY 3100

Squeeky wheel . . . keep trying and calling.

Chevy Duty came thru on a similar wrong part deal that involved the rear end U bolts, they gave me a credit refund.
I'm happy w/ them.

My power master cyl is Brothers, was on sale. It was not a bolt in affair either.
I'll bet they are all pretty much the same set up. I did change the tranny mount but also have a T5 behind a 292. The brothers catalog says you have to remove the X~over support, as I remember.
hope this helps a little.
sorry no help w/ the CPP product.