Posting Page 4

As it is often difficult to e-mail people photos and drawings of large enough size and resolution to be useful I often post replies to peoples questions here. Posting Page 4 is being started June 2011. Hope this page is of use to the individuals asking questions as well as the wider CMP community.

First Question in this new posting page is from Tony

Hi Phil

I am rebuilding a 15cwt C15A for a friend of mine and am trying to complete the brake pipe system. I did not take the Chev apart and am having trouble with the front brake pipe runs. According to the parts book there should be a tee but I am not sure where this should be mounted and how the left hand hose is connected to it.Is the brake system on the C15 the same as the C60 and if so would it be possible for you to mail me some pictures of the brake pipe runs,there is a plan of it in the parts book but it is the same as the US 1 1/2 T0N G506 and I know that it is not the same as I have one of these. I hope that you don't mind me mailing you about this but I am stuck

Thanks and regards Tony

Hi Tony

I’ve got just the photos and diagram that you need and may even be able to give you current part numbers for the hoses. I’ll make a note to dig out the photos and will try and send them out to you this weekend.

What year is your truck? If I’m reading your e-mail correct you have a pattern 12 Cab C15A which means it could have two different routing of the break lines, there was a GM correction bulletin concerning converting from the early brake line to the later design. The original layout was hard to work on and hard to fix leaks. So I want to dig out the Bulletin for you.

As to minding people asking questions, don’t mind at all glad to help.

Cheers Phil

Hi Phil thanks for the prompt reply and for your help. I am not sure what year the Chev is but yes it is a 12 cab C15A. I found some of the original pipes and have made and fitted the rear pipe and hose,then I found a long pipe that runs from the rear frame hose bracket to a double connection at the rear of the master cylinder then found another pipe that seems to run from the lefthand frame hose connection across the front engine cross member,it is the left hand hose connection that I am having a problem with. Is there a fitting that fixes on the frame which the right hand hose is connected to, or is there another metal pipe on that side.?

Thanks once again for your help and look forward to your reply Tony


Hi Tony

To make my response more useful and to get around the image size restrictions with most e-mail servers I am posting the photos and Service Bulletin Pages to my web site. Here is the link to the page, hope you don't mind I am including your e-mails in the web page as a way to format the question and the response in the most meaningful way to you and to others working on CMPs.

Your question and issue of the routing of the front brake lines is an interesting one, First read the service bulletin pages I've posted, from them I think you will see that the problems you encountered are not uncommon the original routing of the front brake lines on Chevrolet CMPs was problematic in a couple of ways first the only practical way to install the line or tighten a connection that leaks is before the engine or any of the body work is installed. The second and probably more important was that the routing of the rubber brake lines put them more at risk of damage from the use of chains or getting caught by brush.

The routing of the lines as seen on page 9 puts the flex lines behind the axle and more out of harms way. But more importantly it is entirely serviceable. That this is an ongoing repair it also complicates the question of what is original and what is not original, but as this is a in-service modification for the restorer I would go with the rerouted brake lines.

Both my own 1941 Pattern 12 C60C and 1942 Pattern 13 C60S have the steel brake routing that goes forward from the master cylinder across the front frame rail behind and under the radiator, see photo. This route for the steel brake line is a hard one to fabricate and get all the bends correct, I think it took me several tries on both trucks to correctly bend the line. It is also very difficult to get the through the frame fitting on the right side to seal and not leak. One thing I can tell you for sure if either of these trucks develop problems with the fittings they will get the Service Bulletin reroute approach.

They both have that special through frame fitting on the right had side. See photos below, I have looked for this fitting as a modern part but have not found it though I will look through the brake hardware catalogs again.

Cheers Phil

1941 Pattern 12 C60L

1942 Pattern 13 C60S right side

1942 Pattern 13 C60S left side

1942 Pattern 13 C60S right side

1942 Pattern 13 C60S right side

Note the spring and clip this is to hold the brake line up and away from shock link.

1941 Pattern 12 C60L right side

1941 Pattern 12 C60L left side

1941 Pattern 12 C60L right side

More pictures to come of the later design for the routing, as used on my 1945 HUP