power brake booster/wheel cylinders/unknown part

[Snags]

Here's a few questions about my 1963 1500.

1. I'm trying to identify the model of power brake booster. My truck had a chassis-mounted camper on it so I don't know if the booster was factory part from GMC or if the camper manufacturer put it on. (I removed the camper because it was getting rotten...and I really wanted a pickup) Can anyone help identify this part, can you buy these still today, or have them rebuilt?? I haven't tried to see if the booster works because I'm going to replace the wheel cylinders and then flush the fluid first.

2. Do you have to remove the front wheel spindles to get access to the bolts holding the wheel cylinders on? Looks like the bolts are right behind park of the steering knuckle with no room for a wrench to get in there.

3. What is that canister mounted on the driver's side fender near the master cylinder? It has a vacuum line connected to the intake manifold and another line going to the oil filter mounting assembly. ?????

Randy

[GMCNUT]

Wow....what a super cool 63 one ton truck. So the power booster is a dealer added "Hydrovac" unit and it is rebuildable - check in Hemmings Motor News under services offered and you will find plenty of brake booster rebuilders. Get your wallet out too - they do not rebuild them cheap. I do not know the answer to the wheel cyl question, and I have so far never seen whatever that cannister is you pointed out, but someone on this board will probably know....let me know if you decide to remove the A/C parts on it for any reason - like to upgrade to more modern A/C etc....I could use a compressor like that

[David R Leifheit]

Here's a few questions about my 1963 1500.

2. Do you have to remove the front wheel spindles to get access to the bolts holding the wheel cylinders on? Looks like the bolts are right behind park of the steering knuckle with no room for a wrench to get in there.


I have a 3/4 ton (1500) sitting out back without a body on it, if I can hack my way through the thick underbrush (mower broke, again) I'll see if I can tell how it mounts.

Or, if I have a few moments, I'll look it up in the manual and see if that has any helpful advice.


3. What is that canister mounted on the driver's side fender near the master cylinder? It has a vacuum line connected to the intake manifold and another line going to the oil filter mounting assembly. ?????

Randy

My "guess", and only because I have a '61 1500 that was similarly modified to become a camper, is that it isn't connected via a vacuum line to the intake, it should be an oil line. It is likely a secondary oil filter, since it connects to the oil filter mounts.

My '61 1500 has something similar, and is the source of many oil leaks. Although mine, as I recall, goes from the filter mount to the "extra" filter, then back into the oil pan through a connection on the side of the pan. Every connection point on mine seems to leak.

What gets me is why some company chose to use 3/4 ton (1500) trucks for this instead of 1-tons (2500). At least they weren't half tons!

[David R Leifheit]

Wow....what a super cool 63 one ton truck. So the power booster is a dealer added "Hydrovac" unit and it is rebuildable - check in Hemmings Motor News under services offered and you will find plenty of brake booster rebuilders. Get your wallet out too - they do not rebuild them cheap. I do not know the answer to the wheel cyl question, and I have so far never seen whatever that cannister is you pointed out, but someone on this board will probably know....let me know if you decide to remove the A/C parts on it for any reason - like to upgrade to more modern A/C etc....I could use a compressor like that

I don't think it is necessarily a dealer addition. That is one of the "stock" options for the trucks. I'll have to pull the manual to be 100% certain, but I am pretty sure the GMC manuals do have instructions regarding this type.

And I know you meant 3/4 ton, not one ton... :)

[raycow]

2. Do you have to remove the front wheel spindles to get access to the bolts holding the wheel cylinders on? Looks like the bolts are right behind park of the steering knuckle with no room for a wrench to get in there.
Try taking the backing plate off the spindle. I think that may be all you need.

Ray

[Rockdriller]

Quote
"3. What is that canister mounted on the driver's side fender near the master cylinder? It has a vacuum line connected to the intake manifold and another line going to the oil filter mounting assembly. ?????"

Randy

Well, as far as I can guess without looking at it...
That is a "Vac. Reservoir". Just like an air brake system uses air tanks to store pressurized air, the larger trucks with juice brakes and vacuum assist need a bit more vacuum at times than is readily available from the engine.
Think about what happens to your vacuum on a long down-grade in a lower gear...
It's nice to have that stored energy when you really need it.
There should be a one way check valve in-line from the manifold.