79 c10 with hydroboost

[79c10al]

So I have recently accommodated a 1979 c10 the thing doesn't have any brake pedal to it at all. I have filled it with fluid and pumped it with the lines off of the master cylinder and it just kind of misted out. So I'm thinking I need a new master cylinder but I don't know which one to get. The truck doesn't have the rpo codes in the glovebox only a sticker about a camper and it has hydroboost on it could it have come original with hydroboost?

 

[1987 GMC Jimmy]

If it's a C10, I don't think so. If you're saying it's a Camper Special, then it would have come with hydroboost brakes, but Camper Specials were only C/K 20's and 30's. Are you sure it's not a C20? What does the camper sticker say? The Camper Special was a truck that came with beefed up brakes, suspension, mirrors, etc. to be ready to go if you wanted to install a truck bed camper. Hydroboost and vacuum boost per Rock Auto use the same master cylinder. Maybe you should check them out to at least get a reference. Don't get one for manual brakes, though. And I'd suggest getting a new one if you're in Spain so you don't gamble with a reman crapping out on you. Are you really in Andalusia? My maternal side originates from Seville, and it's an amazing country beyond description. Welcome to the forum.

 

[skysurfer]

The only C10s with hb in '79 were diesels. I was having problems with my hb system while braking and turning at the same time. The reman pumps I was getting from AutoZone weren't providing enough pressure. Installed a high flow pump from PSC to solve the problem.

Assuming your power steering pump isn't giving you problems and it's fluid level is ok, the easiest way to check for proper hb operation is to pump the brakes 4 or 5 times with the engine off. Continue holding medium pressure on the pedal and start the engine. The pedal should drop slightly and then push back against your foot. If there's no pushback the hb should be swapped out.

 

[79c10al]

Not Spain there is also an andalusia in alabama as far as the truck goes the tag receipt says c10 but it does seem to have a beefed up suspension such as leafs and coils in the rear along with air shocks and a trailer brake controller inside which I'm pretty sure is some aftermarket junk. I'll take some photos of it and see what y'all think. It's at another property of ours and haven't had a chance to do that but it has sat for two years and fired right up and drove it around the property with the e brake. Maybe someone added HB to it trying to make it for towing?