Do you have to pump the brakes?

Phil Waterman · #1 18-08-12, 22:54

Hi All

Particularly those of you who drive your CMPs, I have always been impressed with brakes on CMPs. As only the rear wheels of my HUP has GM brakes I assume that the brakes on Ford CMPs are as good as the Chevy.

I've always kept the brakes adjusted per the book, recently while driving all three trucks over to our MV Club's Rally I noticed that two of three trucks brakes were not the best I remembered. Meaning that pumping the brakes made them work better. Well when I got them home and started checking the adjustment and found that only the most minor of adjustment on the upper cams brought the brakes back to full performance. Peddle has about 2" of travel to hard on.

Has anybody else noted dramatic improvement with only minor adjustment?

Cheers Phil

Bruce Parker (RIP) · #2 19-08-12, 00:50

Quote:

Originally Posted by Phil Waterman

Hi All

Particularly those of you who drive your CMPs, I have always been impressed with brakes on CMPs. As only the rear wheels of my HUP has GM brakes I assume that the brakes on Ford CMPs are as good as the Chevy.

I've always kept the brakes adjusted per the book, recently while driving all three trucks over to our MV Club's Rally I noticed that two of three trucks brakes were not the best I remembered. Meaning that pumping the brakes made them work better. Well when I got them home and started checking the adjustment and found that only the most minor of adjustment on the upper cams brought the brakes back to full performance. Peddle has about 2" of travel to hard on.

Has anybody else noted dramatic improvement with only minor adjustment?

Cheers Phil

I pump the brakes to push around the little air bubble I missed when bleeding the system....

rob love · #3 19-08-12, 03:20

You can keep doing the minor adjustment until it doesn't do it, then back to a major adjustment. But in reality, if you want the brakes to be at their best, the shoes should be contacting in the center. But yes, I have seen where a bit of adjustment can go a long way. But of particular importance is having nice round and clean drums. We have a place in town that still turns the big drums, and the more surface area you can get the more braking friction. Far better to be adjusting your brakes to the overall diameter rather than to a high spot.

I use an air bleeder ball, so air bubbles are not usually a problem. You do tend to go through a lot of fluid with them, mind you.

Keith Webb · #4 19-08-12, 07:57

Quote:

I use an air bleeder ball, so air bubbles are not usually a problem. You do tend to go through a lot of fluid with them, mind you.

Can you please elaborate, Rob?

Bleeding brakes can be a fairly frustrating and messy process, not the least because of the awkward location of the master cylinder filler (in a Ford).

Bob McNeill · #5 19-08-12, 09:06

Used to have problems with BMC,s mainly Mini,s, short of standing them on their noses [ too many dips and high points ] Now I simply fit clear plastic hose from fartherest bleeder to master cylinder, open bleeder topup m/c then pump the crap out of them until ALL air is removed. go to next wheel and so on. NO MESS, only extra fluid required is whats in the hose. CAUTION make sure that fluid does not splash out from bleed hole inside M/c.

Casey B · #6 19-08-12, 22:20

Just to be sure are you saying you create a loop with the hose from the bleeder back to the reservoir in the MC and then as the air is displaced by fresh fliud being pumed in the remaing fluid from the hose goes back into the reservoir?

I used a jar and a hose and do each wheel starting with the farthest and work forward each time letting the air out and the hose stays under the level of the fluid in the jar/can so as to not draw air back into the cylinder if I do not close it off right away or on the downstroke.

Bob McNeill · #7 20-08-12, 04:45

Correct, once the loop is complete, any air is visible, it,s a one person operation, your not getting up and down, filling the M/c every three pumps, knocking over the bottle, just remember to block the end of the hose when changing from wheel to wheel. good luck.

Casey B · #8 21-08-12, 07:18

I see how it will work and not just on the military vehicles. The hose becomes a reservoir as well as a transfer tube...thanks! I'll give it a try next bleed.

rob love · #9 21-08-12, 15:52

Quote:

Originally Posted by Keith Webb

Can you please elaborate, Rob?

Bleeding brakes can be a fairly frustrating and messy process, not the least because of the awkward location of the master cylinder filler (in a Ford).

It is a bit old school these days, but you need to acquire a brake bleeder ball. I have shown a photo grabbed off ebay . Put in the search term "brake bleeder".

Basically, the bottom half is air, then a rubber diaphragm, and the top half is brake fluid. You open the air valve on the bottom, open the filler cap, and fill the ball with fluid. Close the cap, then add air pressure (up to about 30 PSI) to the bottom. You have to open the bleeder valve on top to remove any minor bit of air from the ball. There would be a length of hose running from the top of the ball to an adapter cap for your master cylinder. Usually a spare master cylinder cap can be converted to fill this purpose, or you can buy them. The cap just needs and airline nipple that will match the end of the hose.

Once all this is connected, you turn on the brake fluid, then you can go bleed each wheel station one by one, usually starting at the furthest.

Advantages of the bleeder ball are that it provides constant pressure so it forces out any air at troublesome high spots. It also replaces all the old fluid with fresh fluid, which is actually recommended every couple years in any brake system using DOT3 or 4. Best of all, it is all done with just one person.

Once done, you should drain the air pressure out of the bottom half of the ball, so the diaphragm does not get stressed.

One problem that can occur with a bleeder ball is that the diaphragm can get torn, and the air will all leak up to the top. If you buy an older model, the diaphragm may no longer be available, and you will have to scrap the ball. So it is best to buy a current model. I have had mine for at least 17 years, and have had no problems to date.

I have collected various caps to use on different cylinder. When it comes to the round ones, there are about 4 basic sizes which will let you do about 95% of North American style vehicles. There are also adapters available for the small plastic reservoirs used on modern vehicles, as well as the tin lids used on the 70s era stuff. Snap-on is a good source for some of the more odd adapters.