74 argosy 24' brake questions.

[Trkenn]

Hello.
Trying to locate any diagrams of the brake system, have to replace break lines and would like to know which is front and which is rear on master cylinder, also where the connectors are, not having the best of luck finding any info on brakes for the argosy or for the GMC its built on, thanks for any help.

[martin300662]

Originally Posted by Trkenn

Hello.
Trying to locate any diagrams of the brake system, have to replace break lines and would like to know which is front and which is rear on master cylinder, also where the connectors are, not having the best of luck finding any info on brakes for the argosy or for the GMC its built on, thanks for any help.

Hi Trkenn, welcome to the forum.

The complete chassis manual is available here....

http://www.73-87chevytrucks.com/tech...ice_Manual.pdf

Section 5 has the full brake diagram.

[bkahler]

Welcome to Airforums

You've probably already realized that getting access to the brake lines in the front is almost impossible. In the past few weeks I've been going through the brakes on a 77 20' Argosy and also have my own 20' Argosy that has all of the brake components removed. I do have a bunch of pictures that I can post to help give you an idea of how the brale lines look up front.

Tomorrow I will probably have the radiator out of the 77 and can get detailed pictures as to which brake line from the mc goes where.

Brad

[Trkenn]

thanks that might help. im trying to replace the front lines and i am having trouble tracing them back to the master cylinder they usually t off somewhere then back. fairly simple to replace just need to know where they all go.

[martin300662]

Originally Posted by Trkenn

thanks that might help. im trying to replace the front lines and i am having trouble tracing them back to the master cylinder they usually t off somewhere then back. fairly simple to replace just need to know where they all go.

That's because they go to the proportioning (combo) valve after the MC, and the proportioning valve outlets head off to the brakes.

[bkahler]

Based on Martin's picture of the proportioning valve and this picture of my original brake lines it would appear the front pipe on the M/C is for the front brakes.



And speaking of proportioning valves, any idea on where to find a replacement for a 74 P30?!

Mine needs to be replaced.

[martin300662]

I think they are fairly standard for 1 ton JB8 brake setups (JB8 is the hydroboost, front disc, rear drums vs JB9 for discs all around).

I was told the JB9 has a different spring due to a different brake bias between front and back and the proportioning valve needs to be changed if you ever have to upgrade to rear discs.

Dan the mechanic who repaired my brakes sourced one direct from his normal parts place.

[bkahler]

Looking through my 73-87 GM parts books I found two different numbers that seem to correspond to my chassis. Looks like about $80 or so plus shipping.

Guess I better get one on order.

Thanks.

[Trkenn]

Turns out everything that was sent was a big help. Happend to be a new to me type of system, never seen one that ran through the power steering before, nice to know something old can show you something new.

[mprokop87]

I can confirm that the line further forward on the MC is for the front. It should be coming out of the bigger reservoir (open the cover to check which is bigger) because it goes to calipers VS the drum brakes.

I just went through my brake system because I had to replace the hydraboost unit and master cylinder. Those front lines are a bit of a pain to get at but it can be done!