rear wheel brake cylinders

[FJROSS]

I doubt that the design of CCOT cylinders makes them unusually hard to bleed because this is the way most wheel cylinders are made. If you bleed them with gusto, there is so much turbulence from the fluid swirling inside the cylinder that the bubbles come out no matter what the volume inside the cylinder is. It just isn't a problem if you really bear down on the pedal when you are bleeding. Properly done the fluid will shoot about 3-5 feet before it hits the ground. Self bleeders can allow air to leak back into the cylinder and vacuum and some pressure bleeders do not have the gusto to get the bubbles out. I worked in a shop that averaged about 8-10 brake jobs a day and we only used the 2 person manual bleeding method because it worked 100% of the time and it was faster. Time is money and cars that come back a second time to fix cost money.

One of the problems many people describe, the pedal going to the floor and rising when the pedal is pumped, is not due to air in the cylinders but rather improper adjustment. Bubbles just make the pedal spongy. Some people never adjust them tight enough because they worry about them dragging. Dragging is normal on a properly adjusted drum brake.

I beg to differ with you with the way the economy ccot wheel cylinders are constructed. My fleet mechanic of over 30 years experience is very familiar with performing brake jobs and bleeding the system.The oem wheel cylinders have a spring, metal cap and a seal that goes on top of the cap which I believe helps displaces the void that the economy ccot cylinder creates. Ccot cylinder only have a spring and a domed rubber seal with out the metal cap. I tried to achieve a hard pedal over a dozen times trying the manual pump and bleed method and then went to vacuum bleeding and pressure bleeding. None of these method worked until I disassembled the cylinder in place and burped the seal under fluid. When I get a chance, I will post up some pics of the oem vs the economy ccot cylinders construction. I was not the only person that commented on having problems with bleeding these ccot cylinders. I even adjusted my shoes all the way out to the point where the drums were locked to eliminate that the drum adjustment wasn't the culprit and even isolated the front brakes and then each rear side to see if I could find a bad cylinder or so forth. I also have read many posts where people are still living with pumping up there brakes to achieve a hard pedal. I recently switched over to rear discs and will never have to deal with this problem again. For any one sticking with rear drums, I would recommend purchasing the oem type cylinders.

Dave

 

[KOOTENAY KRUZER]

I have never had this spongy pedal problem when bleeding the brakes, I usually just open the bleeder one cylinder at a time and let the fluid run through, keep the reservior full, sometimes have to pump the pedal once or twice to get the flow started but after that gravity works (same technique as bleeding brakes on small aircraft). Of course, if you have help, pumping the pedal while opening and closing the bleeder can be quicker.

That is with both the 2 cylinder per wheel setup and the 1 cylinder per wheel setup.

The only time I have ever had to pump the brakes twice to get a hard pedal is when they are out of adjustment. To adjust them I have always tightened them until the wheel is real stiff, push the brake pedal hard to center them, tighten until the wheel won't turn, then back them off 'til I could rotate the wheel by hand through a full revolution but the brakes were still dragging. If they feel a bit too stiff just stop after a few miles and feel the axle hub. If it is warm but not too to hot to touch don't worry about it, the brakes will "seat" themselves (wear in) and be fine for the next few thousand miles.

This is with OEM cylinders that are still functional, not seized or leaking.

 

[F-junker]

I run oem disk forward and drum aft. I ran only oem rear cylinders due to the lack of quality I found with other cylinders available from CCOT and others. Once my shoes were adjusted properly (yeah it took awhile for me to remember to do this prior to bleeding!) bleeding was not a real difficult issue.
I replaced my entire system at once. Hard S.S. lines front to back etc. etc. master cylinder, the whole ball of wax. DO NOT cut corners on your brakes, they are in fact the most important part of your truck.

BTW- the brakes on this truck are so damn good I can't believe it. They outshine the brakes on my mini-truck by a mile, I've tried to get my mini-truck to brake better and can't. I'm guessing the single cylinder in the rear in weaker and the master is also a weaker unit as well. I've really got to stomp on the sob to get them to work well. Go figure?...