New to me 1962 GMC B4000

[RSMCCRAW]

Hey everyone!
I picked up a B4000 the other day for 500 bucks.
I was wondering if anyone had any parts numbers or sources of information that I'm needing.

Mainly I need a Brake Master Cylinder. It has vacuum assisted power brakes.
Also the brake booster that sits underneath the cab would be great to have a replacement if the master cylinder isn't the only thing wrong with it.

Does anyone have any other brake shoe part numbers or anything else I might be able to use to source brake parts? Im having a lot of trouble finding part numbers or anywhere to purchase parts for this thing.

It runs great, it has the 305 v6 in it and it starts up on first bump.

Here are some pictures.



My first priority is going to be replacing the wheels. These are definitly the RH5's and I dont even like them sitting in my yard with pressure.

Thanks for looking everyone, I look forward to hanging out here.

[Okiefromwatonga]

Awesome rig! Here is a parts rig if ya need one
http://dallas.craigslist.org/dal/cto/5406010300.html

[DPowers]

You might find some info here:
http://6066gmcguy.com/

[RSMCCRAW]

Originally Posted by DPowers

You might find some info here:
http://6066gmcguy.com/

I've looked all over that site, but I havent been able to find any part numbers that I think will work for looking up specific parts for my GMC 4000, all of his lists seem to center around the 1000 and 2500 series.

[Katrina/10]

Cool truck!

[C10 - C90 Bill]

Originally Posted by RSMCCRAW

I've looked all over that site, but I havent been able to find any part numbers that I think will work for looking up specific parts for my GMC 4000, all of his lists seem to center around the 1000 and 2500 series.

If no one jumps in to help, there is a parts expert over at Stovebolt.com

Go to the Discussion Forum and once there check on "Big Bolts".

You also may want to get some original GM Parts Manuals as well as some Service Manuals to help. They are pretty much available online.

Bill

[63 & 64 Bowties]

First, welcome to the forum!
It might be a long shot, but do you have a local NAPA store?
I had a 64 International years ago and asking for parts at the big-box parts stores, I got a blank deer-in-the-headlights stare, but my local NAPA store had tons of parts in stock and in the store. It's worth a shot.

[JPBrecheisen]

Originally Posted by RSMCCRAW

Hey everyone!
I picked up a B4000 the other day for 500 bucks.
I was wondering if anyone had any parts numbers or sources of information that I'm needing.

Mainly I need a Brake Master Cylinder. It has vacuum assisted power brakes.
Also the brake booster that sits underneath the cab would be great to have a replacement if the master cylinder isn't the only thing wrong with it.

Does anyone have any other brake shoe part numbers or anything else I might be able to use to source brake parts? Im having a lot of trouble finding part numbers or anywhere to purchase parts for this thing.

It runs great, it has the 305 v6 in it and it starts up on first bump.

Here are some pictures.



My first priority is going to be replacing the wheels. These are definitly the RH5's and I dont even like them sitting in my yard with pressure.

Thanks for looking everyone, I look forward to hanging out here.

Are you sure the two on the front are RH-5? Those look like the tubeless 22.5 design.

I went through the same thing. I ended up getting the re-pop version from wheels now. I think its a 28160J. Here is a pic of how they look installed with a 10R22.5 tire.

I have two factory firestone 22.5 tubeless wheels posted in the 60-66 parts board that I won't need anymore.

I also think I have two parts books that cover that year and model. I will take a look and see what I can find. If you look on ebay the parts books come up now and again. They're worth the investment. As far as the brake linings go, you can have them re-done. I'd recommend this. There are places out there than can rebuild the hydrovac assemblies also. Some of the stuff on those big truck has to be rebuilt as finding spares it a challenge.

Awesome truck BTW

Jonathon

[63 & 64 Bowties]

Originally Posted by JPBrecheisen

Are you sure the two on the front are RH-5? Those look like the tubeless 22.5 design.

Funny, because I was thinking the same thing. I just assumed he would know since he's there.
But even the rear one looks like you can see the break-down well on the wheel. To me, they all look tubeless.

[RSMCCRAW]

Thanks everyone so much for the help so far.

I'm getting closer and closer it seems.

I'll get some better pictures/closeup tomorrow when I get back home from work of the wheels. They definitely have a split in the middle of the rims on the rears, I haven't gotten too up close with the fronts but I am really in a new world with these medium duty trucks.

I've ordered a parts manual as well as a maintenance manual.
Working on ordering rust free hood sides and cowls and getting some patch panels for the doors.

[JPBrecheisen]

Originally Posted by RSMCCRAW

Thanks everyone so much for the help so far.

I'm getting closer and closer it seems.

I'll get some better pictures/closeup tomorrow when I get back home from work of the wheels. They definitely have a split in the middle of the rims on the rears, I haven't gotten too up close with the fronts but I am really in a new world with these medium duty trucks.

I've ordered a parts manual as well as a maintenance manual.
Working on ordering rust free hood sides and cowls and getting some patch panels for the doors.

Good deal. You'll find those books very useful. I know I sure do.

Good luck with the project and keep us posted. I took a look at one of my books and it only covers through '61. I have another that covers later years, but not sure it goes back that far. I will take a look and lend a hand if you hit a dead end with the books you ordered.

[RSMCCRAW]

https://www.youtube.com/watch?v=ucN1E7hWk4M

If you guys dont mind watching this and letting me know if they are the RH5's. The wheels are 20 inch.

Also I'm running into another issue with the brakes. I think they've been rigged up, but i'm not certain. I'll post a few pictures with descriptions.

Thanks for the help again.

[RSMCCRAW]

Here's a video of the weird brake setup, because I think it may be easier to convey what I'm talking about through that than through typing.

https://www.youtube.com/watch?v=nntFeNlmnYs

The service manuals I have found online do not show any third line like I have on my master cylinder.
It appears that if I made/installed a reservoir closer to the 2-speed rear end controller or whatever that is in the video would serve the same purpose as the brake line coming from my master cylinder, It seems like a bad idea to be able to lose brake fluid to a leak in a different system than my brake lines.

Let me know what you think and if you have any ideas.

[RSMCCRAW]

Sorry if the video isn't clear, the master cylinder I have to replace the old one with has no hole/fitting on the front.

[Okiefromwatonga]

Those wheels sure look like these RH-5's

[JPBrecheisen]

Originally Posted by RSMCCRAW

https://www.youtube.com/watch?v=ucN1E7hWk4M

If you guys dont mind watching this and letting me know if they are the RH5's. The wheels are 20 inch.

Also I'm running into another issue with the brakes. I think they've been rigged up, but i'm not certain. I'll post a few pictures with descriptions.

Thanks for the help again.

Originally Posted by RSMCCRAW

https://www.youtube.com/watch?v=ucN1E7hWk4M

If you guys dont mind watching this and letting me know if they are the RH5's. The wheels are 20 inch.

Also I'm running into another issue with the brakes. I think they've been rigged up, but i'm not certain. I'll post a few pictures with descriptions.

Thanks for the help again.

The rears do look like RH-5. The fronts however look like split rim, but might be the multi-piece type. The center (disk) doesn't have the normal RH-5 look to it. They have spade shaped holes for that era. I wouldn't mess with a RH-5 unless you really know what you're doing and there isn't a tire shop that knows what they are that will touch them. Finding 20 inch rubber is difficult and the 22.5 radials ride better. I am happy I made the switch on mine. Not cheap, but worth it. I did save money by doing re-cap tires though. For what little my C60 sees the road, I am not concerned. Some think you can't run a re-cap on the front, but regional trucks do it every day. Its the over-the-road and highway trucks that shouldn't run them. But a garbage truck that sees maybe 45 MPH all day, its fine.

Now on your brakes....I posted a few pics here. The parts book is for Chevrolet, but looks like the two master cylinders that would be the equivalent is either 5467735 or 5467734. I would measure the bores. One is 1-1/8 and the other 1-1/4.

The "missing" port on your replacement unit looks like a compensation line for the vacuum assist. I posted a diagram out of the 1962 GMC parts book along with some text describing its function. I don't think it actually runs to your two-speed axle mechanism. I think you just may have mis-traced them from the firewall going back. I think what you grabbed near the frame rail in your video is a control for the two-speed actuator. I posted a diagram of that as well.

If your replacement master cylinder is the correct bore, just take some measurements of the port location on the old one and drill/tap your new one in the same location. If you don't have experience with this, ask a friend or machinist to help. Be sure not to let shavings get into the ports of the cylinder mechanisms.

Hope this helps.

Jonathon

[VictoriaHardware]

The service manuals I have found online do not show any third line like I have on my master cylinder.

Yes you must have that third brake line. The diagram in the previous post is a good one.

The inboard bore (in truck mounted position) is the clutch master cylinder. It controls the clutch slave cylinder mounted on the belhousing.

The outboard bore, which is larger, is the brake master cylinder and controls the brake slave cylinder which is mounted to the frame.

The third line is for the reservoir for the brake slave cylinder. Note that the pressure in that line it is low (essentially zero) pressure.

So the reservoir in that casting mounted high on the firewall is for 3 things- the clutch master, the brake master, and brake slave cylinders.

As noted above, there are two different brake bore sizes- 1 1/8" and 1 1/4" . Measure your old to be sure because the books can be confusing. Measure the clutch bore while you're at it.

If everything else about your new master cylinder is correct, then adding that brass fitting for the third line will work. BTW It is a pipe thread going into the casting.

[JPBrecheisen]

I highly recommend you search for this manual and purchase. You will need it to repair that truck.

Just do an online search for 1962 GMC shop manual.

[jumpsoffrock]

The fronts are still RH5º, I'm 95% sure. My truck came with 2 different types of RH5º, the hand holes were different for sure, but they ware all stamped RH5º anyways.

In your first video, the shot of the inside of the wheel is somewhat of a giveaway.

[66-PMD-GMC]

That's my dream truck right there.....