I know some of you guys are or have been heavy truck machincs so I am hoping that you can give me some guidance.
I have an 1973 international loadstar dump truck that I use for plowing snow. I have started having trouble with the brakes.
The brake system is vacuum assisted and it suckes the brake fluid out of the master cylinder.
I don't have a clue as to how it all works so I am looking for a diagram of the system or a repair manual.

Now I know about this form. I do have a 1993 Dodge diesel that has been trouble free for the three year that I have owned it. When I got the truck it had 53k and now it is up to 83K.
Any how thanks for any help that you might be able to give me.

 

Loadstar I bet your talking a 1600 most likely. It has a single line master cylinder mounted on the firewall with a hydrovac booster mounted under the cab.

If that is the setup it uses I bet the hydrovac needs rebuilt. That is if you do not have any traces of leakage from a blown wheel cylinder on the brake drums or backing plates.

BTW 30k in three years on the CTD means your letting it set to much.

 

Philip the truck is a 1600. I could not remember when I did the post.
Ya, I know the truck is setting too much but I can't afford the fuel.

Thanks for the reply. I did find an old repair book that describes the system.

 

I forgot to mention the easyest way to check that hydrovac is to remove the vac line off of it. If brake fluid comes out of the hose or the inside is wet. Then it is leaking internaly.

Replace it.

 

what philip said if your vac line is wet they you need a new master cylinder