M37 Brakes

[slk]

How good should the brakes be on an M37? I realize they are not power disk, but I have to press down hard to get the truck stopped if you are going fast. I have found if you pump them once they are much better. Just wondering if this is normal and I need to get use to it.

Steve

[cuz]

It is very difficult to quantify the quality of your braking system on the phone or the internet. You should find a local experienced antique/classic vehicle mechanic who can try your brakes and give you an accurate assessment of their condition. Unless you have driven thousands of miles in older type manual brake vehicles you will not be able to draw anything resembling an accurate view of your brake system's performance quality.

I am not trying to blow your question off here. I am trying to point you in a better direction for help when the importance of the system (IE brakes & steering) is high from a safety stand point.

[MSeriesRebuild]

How good should the brakes be on an M37? I realize they are not power disk, but I have to press down hard to get the truck stopped if you are going fast. I have found if you pump them once they are much better. Just wondering if this is normal and I need to get use to it.

Steve

If you are having to pump the pedal to get decent brakes, this is not normal. Either the shoes need to be adjusted closer to the drums or the check valve in the master cylinder is not holding are the typical causes of this in the original system.

[8543bob]

Good Morning,
I had a similar situation, check the fluid level in the master. If its low then start looking for the leak.
Good luck, Bob

[slk]

Fluid in the master cylinder is to the top and not leaking down. I do have to pump the brakes 1 or 2 times for it to have good brakes. All the shoes look fine and are adjusted like they are supose to be.

[cuz]

I do have to pump the brakes 1 or 2 times for it to have good brakes.

All the more reason to have a professional take a look at it. Running over a 3 year old kid because you couldn't get the 2nd pump quick enough will have a serious impact on your ability to sleep at night.

[Master Yota]

I would remove the MC resevoir cap, and observe the fluid while the brake pedal is depressed. If fluid leaks back into the master while the pedal is under pressure, then the MC is kaput. A spongy or soft pedal may also indicate air in the brake system. I would try bleeding the system again to achieve a firmer pedal.

[MSeriesRebuild]

Fluid in the master cylinder is to the top and not leaking down. I do have to pump the brakes 1 or 2 times for it to have good brakes. All the shoes look fine and are adjusted like they are supose to be.

If you are certain the shoes are correctly adjusted, (many have the opinion that they are when they really are not) then the check valve in the master cylinder is not holding residual pressure. A loss of residual pressure in the system is why the pumping is needed in order to build pressure back up so you have a good pedal. This is a common problem, the best fix is to replace the master cylinder, as typically rebuilding does not produce a desirable outcome.

[slk]

I am thinking I will replace the MC . At least that way I can be sure that is not the problem.

Does any know of a cross reference # for these at Napa or a parts # for them????

Steve

[cuz]

Steve,
NAPA shows their PN 544 http://www.napaonline.com/Search/Detail ... 0192387721#

Brake Master Cylinder - New
Product Line: NAPA ULTRA PREMIUM BRAKE PARTS
Part Number: UP 544
Price:
Price: 144.00
Unit: Each
Features & Benefits Designed To Match O.E. Fit, Form & Function.; High Quality Rubber, Smooth Bore Finishes & Properly Threaded Outlet Ports Ensure Trouble-Free Operation.; Compatible w/ DOT Approved Silicone- Or Glycol-Based Brake Fluids.; Reservoir Fluid Level Switches Included Where Necessary.
Warranty Limited Lifetime-See Manufacturers Written Policy
Warranty PDF
Attributes # of Line Ports : 2
Brake Master Cylinder Bore Size : 1 1/4"
Brake Master Cylinder Line Thread Size : (1) 1/4" - 18 NPT & 1/8" - 27 NPT & (1) 3/8" - 18 NPT
Material Safety Data Sheet There is no MSDS for this item

[MSeriesRebuild]

I am thinking I will replace the MC . At least that way I can be sure that is not the problem.

Does any know of a cross reference # for these at Napa or a parts # for them????

Steve

We have new F544 master cylinders in stock for $75 plus shipping.

[cuz]

The NAPA number was just 544. What brand/manufacture are the F544's?

[MSeriesRebuild]

The NAPA number was just 544. What brand/manufacture are the F544's?

F544 is a Wagner part#. We have stocked and used these for years, always a good result.

[slk]

Do you have to reuse the lower pipe plug,brake switch,brake line adapter& original master cylinder cover w/ vent fitting on those 544's.

[cuz]

Your $75 is one HUVA deal since I found all other listings asking $95 to $200 for the F544, But I only found a couple that actually said made by Wagner! The suggested retail was over $300.

Wagner F544 Brake Master Cylinder
Model: F544
Manufacturer: Wagner
Price: Retail Price: $303.99
Our Price: $199.99
http://www.autoplusparts.com/index.php? ... gp0dv6rom5

MASTER CYLINDER, DODGE M37 F544, 1269447
Item# F544
$95.00
Product Description
Master cylinder for M37 3/4 ton trucks.
http://store.midwestjeepwillys.com/1269447.html

The photo of this one looks like a repop.