Wheel cylinder direction

[tarawa]

I have been working on the brakes of my M37 and I believe the previous owner didn’t pay attention or know that wheel cylinders are left and right. I replaced them as I found them and now I may have them on backwards. Large cylinder facing forward (front shoe) or towards rear shoe? Back to the drawing board for me. Luckily I haven’t added fluid or bled brakes yet.

[tarawa]

Note that only one cylinder seemed to be marked with an R.

[Blue Chips]

I have been working on the brakes of my M37 and I believe the previous owner didn’t pay attention or know that wheel cylinders are left and right. I replaced them as I found them and now I may have them on backwards. Large cylinder facing forward (front shoe) or towards rear shoe? Back to the drawing board for me. Luckily I haven’t added fluid or bled brakes yet.

For my 1954 M37:

Per TM 9-8031-2, Paragraph 169, e. Install Wheel Cylinders
Note: The location of the wheel cylinders is indicated by the letters "L" and "R" cast into the wheel cylinder body designating left and right and must be installed accordingly. This identification is provided because large bore of cylinder should always be toward rear of vehicle.

Per TM 9-8030, Paragraph 213, b. Data
Wheel cylinder bore:
Front shoe (all)....1 1/4 in.
Rear shoe (all)....1 3/8 in.

It should be the same for an M37B1:

Per TM 9-2320-212-20, 2-131. Brake Shoes and Wheel Cylinder
a. General. Front and rear brake shoes for all wheels are identical and hence interchangeable. Wheel cylinders are marked L or R for left or right
wheels, respectively, and must be installed accordingly. When brake shoes for one of the front or rear wheels require replacement, replace the
brake shoes for the other front or rear wheel at the same time to insure proper equalization of the brakes. Procedure is the same for all wheels.

Per TM 9-2320-212-20, 1-8. Tabulated Data
Wheel cylinder bore:
Front shoe ................ 1 1/4 in.
Rear shoe ................ 1 3/8 in.

[ODAddict]

Excellent info from Blue Chips.

The manuals are an excellent source for all aspects of the M37. I'm finishing a complete rebuild of my truck, and the manuals are indispensable. They remove a lot of opinion and second hand information while greatly increasing your personal knowledge base.

I got hard copies(very useful in the shop) from Portrayal Press.

[tarawa]

I decided to purchase new wheel cylinders …..two right and two left

[tarawa]

New wheel cylinders, shoes and master cylinder are all replaced. Correctly this time around. Next I will bleed the brakes then off to the engine.

[Blue Chips]

Make SURE that you adjust your brakes correctly. A lot of M37 owners don't follow the correct procedure. Follow the specific sequence for a "major" or
"minor" brake adjustment as described in the appropriate technical manual for your M37-series vehicle. It can make a huge difference in how well your brakes work.

[tarawa]

I believe I got it right using the feeler gauge method and adjusting both the upper and lower adjustments. If it’s not perfect, it is darn close.

[Blue Chips]

I believe I got it right using the feeler gauge method and adjusting both the upper and lower adjustments. If it’s not perfect, it is darn close.

Sounds good. Ideally you want to achieve full lining surface contact with the drum when the brakes are applied, and with very little pedal travel, but without dragging when not applied.

Another thing that can be done to reduce pedal effort is to have the shoes relined with a compound that has a higher coefficient of friction. There are various compounds available. Be sure to also check the fade resistance, etc., for the different compounds.