The Stovebolt Site Forums The Shop Area Driveline Brake Replacement Tips - 54 1/2 ton

Hello - I'm seeking out tips/tricks from experienced stove bolters specifically on replacing the single master cylinder (with a rebuilt single) on my 54' 1/2 ton. I've owned the truck for a little over a year..so not the most experienced with them.

As these things often occur, the job started with replacing a leaky wheel cylinder. When I got in I realized the wheel cylinder, along with one on the other side, were original or darn near original. Soft lines were old, and stiff...and hard lines were fused. One thing led to another...and I decided to replace all brake hardware, hard and soft lines and master cylinder. I want originality...so not upgrading to disc or dual MC.

Ok, the job looks pretty straightforward...even for a shade tree mechanic, like myself. However, I'm admittedly a little intimidated on how best to access/remove the nicely hidden MC. I have the shop manual, which is great for the basics, but was hoping a search in the forum would lead to a nice write up by someone...but no go.

So, a long story - long - can anyone provide tips on removing/replacing the M/C? Any other tips as they relate to the hard lines? I see there are to lines coming out of the back of the M/C...not familiar with the fitting on the back.

Thanks in advance!

Kevin

This may be helpful:
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0523.htm

The holes that go through the MC are for the mount bolts. Two of them just about the middle up and down. The bolts go through the frame and into a plate that is threaded. It is all straight forward when you get it clean and apart. Take the lines off, Remove the push rod, take put the two bolts and it will be in your hands.

Oh ueah, do it from under the truck..:)

Hi, I'm not all that experienced but I had my master cylinder on and off 3 or 4 times a couple months ago. It really is a piece of cake.

The cotter pin connecting the push rod to the pedal arm needs to be removed. Grasp it with a pair of snub-nose pliers and give it a sharp tug. A flat head screwdriver is helpful to bend the tang on re-installation.

My M/C had two hard brake lines - these get removed next. It's probably best to use a flare wrench on these to avoid stripping anything. Re-installation of the hard lines is a little tricky because they have to be square to get them started. Maybe try to start the nuts by hand to make sure they are not cross-threaded.

If you are having trouble getting the hard lines installed, you might want to connect the lines to the master cylinder before securing it to the frame. Or at least leave the two main bolts loose. This allows both parts to move and a little more freedom or wiggle room to get the nuts started.

You might have to bend the hard lines just a little bit, especially if the end-cap on the master cylinder was removed. If so, be careful not to crimp the lines.

Two bolts secure the master cylinder to the frame, and they thread into a single flat iron with two threaded holes. I found it easiest to use a tapered punch (pin) to line up the front hole (closest to the engine) while installing the bolt in the rear hole loosely. Then install the front bolt and tighten up everything.

The push rod gets adjusted so the pedal arm is 13/16" away from the toe-board / firewall. I used a piece of 1 x 2 as a 3/4" spacer (close enough I think).

Also, you might consider bench bleeding the master cylinder before installation. And for me, I found the "speed bleeder" valves handy for bleeding the brakes.

Big help.....thanks guys!

When working with the hard brake lines and the flare fittings, it is best to get yourself the proper brake line wrenches. These help avoid rounding off the hex shoulders of the fittings. This applies to both removing the old rusty crusty original lines, as well as the new lines. Also, when assembling the new lines, it is very easy to cross thread the new fittings, so best to start them by hand to be sure you got it right before tightening with your new wrenches.

Kent