Rear brake getting hot?

[mancoman]

My 250 buggy has 2 front disk brakes and one caliper and rotor rear brake to the right side of the axle.The problem is the rear brake rotor gets very hot while the 2 front stay cool except when I come down a steep hill and all 3 get hot but like after normal road running like today the rotor gets so hot I can't touch it!I know brake shoes are supposed to float on the rotors but this is more like it is sticking and causing drag and cutting the speed down.I don't have an emergency brake right now cause the cable is broke but I have a new cable and have to install it yet-could this have anything to do with this problem? mancoman

[x-bird]

jack the rear up and see if the pads are dragging, if not, then that aspect is ok. is there an adjustment for front/rear bias? some have adjustable rods in the master to let you adjust which circuit gets more pad travel.

[metalstudman1]

Spray some WD-40 on the caliper sliders (there is 2 of them,usually under/out to the sides) to help the caliper slide it alittle. My rotors get warped and wobble some when we're out tearing it up because they get so hot, spraying the carriers helps.

[mancoman]

Photos of rear single brake caliper and front master cycinder.This has a modual that the brake pedal has to be pressed before engine will start.Also have an old caliper that came off buggy last year and can post photos if needed. mancoman

[mancoman]

Forgot to post photos.mancoman

[mancoman]

Couple more photos. mancoman

[metalstudman1]

Just a tip- if you feel the rear pads are staying too tight against the rotor, it could be that the pistons are just stuck or don't have enough free movement. Pry the pads apart and free up the caliper, usually one pump on the brake pedal right after get's them right again. Spraying WD-40 on the rods where the little rubber tips are helps the caliper travel side to side smoother if the rotor has a small warp.

[mancoman]

What can I use in prying the shoes apart and not damage shoes or rotor?Photos of the old rear caliper which is exactly like the new I have now. mancoman

[metalstudman1]

I use a stiff putty knife or a screwdriver, it depends on if they will move at all. When did you replace the caliper? Is the one on the buggy now just get replaced?

[mancoman]

metalstudman1 computer crashed late last night-had to wipe it clean and reinstall drivers to rid the trojan and just got it going...........the new caliper was installed about a year ago.There is nothing absolutely nothing wrong with the old caliper except may need new shoes and it got hot just like the new.I have checked for a wobble warp and could not see one? mancoman

[edroden]

I would suspect that maybe the parking brake arm isn't completely released or the brake hose may be collapsing. Open the bleeder screw to let a little pressure off and see if it spins freely, if it does then its probably the brake hose.

P.S. Glad to see you found a new home!

[mancoman]

edroden good to see you as well.The guys here have been very helpfull in trying to solve problems as I am very gratefull. mancoman

[metalstudman1]

I assumed you'd already loosened the parking brake a little as that usually is the first culprit for a dragging brake.Have you already adjusted it?

[mancoman]

metalstudman1 the parking brake is not working and needs to be replaced.Tried screwdriver to pry apart but did not have much time to look at tonight.Hope to do more tommorow my friend suggested a light bleed? mancoman

[metalstudman1]

I agree with the light bleed but only after the caliper pistons are confirmed free-d up. When the piston in the caliper sets for extended length of time the get stuck-usually just prying them open a little free's up the piston.That process is similar to a light bleed except no fear of spongey pedal when done.
The parking brake is the mechanical portion of the caliper, loosening/tightening the big bolt/nut on the side of the caliper adjusts the piston depth for the cable to activate the brakes without hydraulic pressure. Try loosening it up and see if your pedal still applies enough pressure to lock up the brakes.

[kliff]

I would hope this problem has been solved by now, but let me throw out a few ideas, just in case it hasn't.
#1 Chinese brake fluid is the WORST! ALL brake fluid is HYDROSCOPIC, it attracts water and absorbs it. Even in a closed system, water can be sucked in through the master cylinder vent.

#2, as bake fluid heats up, ANY water in a caliper will turn to steam. This steam will keep pressure on the pads, and cause a "hot brake."

#3, and I can't explain this one, but when water enters a braking system, it seems to migrate as far from the master cylinder as possible, hence the rear brake.

#4, another sad fact is that ANY amount of water, no matter how small, in a caliper, will cause erosion and corrosion of the aluminum it is made from. This corrosion can also cause the caliper pistons to stick. Best solutionif this is the problem is replacement. Though I have on occassion, rebuilt caliper with Viton ound or square section "O" rings, bought at my local bearing store. Viton "O" rings will take high pressures and temps. DO NOT go to your local hardware store. Go to a bearing or hydraulic shop, with your old "O"rings and dissassembled caliper, and have the matched up.

Hope y'all have already fixed MM problem, but maybe this will help someone in the future.

[ckau]

Sorry to go off topic in your thread Manco. I just wanted to say- Kliff, it's truly good to have you back in the game, buddy!
kliff brings up a very good point about moisture in these systems. Any brake system not used on a very regular basis forms condensation in the lines. These china systems are the worst! Let them sit for just a few weeks. calipers stick. most of the time they free up with a few minutes use but repeated irregular use leads to corrosion and the problems described. Actually, the worst thing you can do to a china buggy is not use it!

[x-bird]

if you can't get them to move (pads) after all else, seal off the line hole or bleeder hole and use compressed air to pop the pistons, Wrap with rags before doing, keep fingers clear and point away from anything you value.

[mancoman]

Any mechanic will tell you that auto brakes the front will take the most load in stopping but is that true in a buggy rated at 573lbs empty?But add my skinny butt at 145 lbs and a tank of gas and oil should be well over 700lbs so with the buggy having 2 front disk and one rear disk brake does this change the rule to the opposite?.........I thought of leaving the rear caliper connected to the hydrolic brake line and taking it loose off the rotor and pedal pumping the piston as far out as it will go and then greasing the piston and use a screw clamp to have it to depress-do this 4 or 5 times to get the piston to start to move more freely instead of the "frozen" state it is now???Just an idea and a big Thank You to you guys trying to help me. mancoman

[x-bird]

same holds true as far as application of stopping power---you want front bias. maybe some penetrating oil instead of grease for your method. once it's freed up though, i'd disassemble it and inspect/rebuild it.

[Ironknot-Buggy]

How is the movement when you move the E-brake lever, I wouldn't force the lever too much at all but if it will work a bit, repeated action may clear the crud in the action.
The faster you go the more momentum is you have, the brakes end up trying to do a reverse wheelie with all the weight (momentum) on the front and the stopping force compressing the front and lifting the back, with the back being lifted there is less traction.
I've been told that some people leave a bit of pressure on the brake pedal and this can cause some drag, maybe check how much pressure/travel the pedal uses to contact and look at a stronger return spring on the pedal so your foot resting on the pedal isn't causing drag.

[kliff]

Originally Posted by mancoman

Any mechanic will tell you that auto brakes the front will take the most load in stopping but is that true in a buggy rated at 573lbs empty?But add my skinny butt at 145 lbs and a tank of gas and oil should be well over 700lbs so with the buggy having 2 front disk and one rear disk brake does this change the rule to the opposite?.........I thought of leaving the rear caliper connected to the hydrolic brake line and taking it loose off the rotor and pedal pumping the piston as far out as it will go and then greasing the piston and use a screw clamp to have it to depress-do this 4 or 5 times to get the piston to start to move more freely instead of the "frozen" state it is now???Just an idea and a big Thank You to you guys trying to help me. mancoman

Manco, I'm afraid what you'll end up doing is popping the pistons out of the caliper body attempting that method. They won't come out too far, before they come beyond the "O"rings anyway. That is another good, but messy, way to get the pistons out, if you don't have access to air though.
If the corrosion has set in, between the piston and caliper, grease won't really help. The corrosion is a solid matter that takes up room between the piston and caliper bore, and needs to be cleaned out, not lubricated. If possible, and I understand fixed incomes, on one myself, get a new caliper, and in your spare time, rebuild the old, then when needed, rotate them out. That way you keep a freshly built caliper on the shelf. Cause like was said, storage does more damage than use.
Hope this helped...

PS, you are correct, aproximately 70% of your braking power comes from the front brakes on your buggy.

[toomanytoys2]

Originally Posted by mancoman

Any mechanic will tell you that auto brakes the front will take the most load in stopping but is that true in a buggy rated at 573lbs empty?But add my skinny butt at 145 lbs and a tank of gas and oil should be well over 700lbs so with the buggy having 2 front disk and one rear disk brake does this change the rule to the opposite?......... mancoman

Actually for off road use our bias should be more to the rear. It is not an issue of stopping power, but more for control. If you look at full sized sand rails, many of them do not have front brakes. The problem with forward biased brakes in the dirt is locking up the wheels. So if you go into a turn a little hot and hit the brakes and try and turn at the same time, the fronts lockup and just plow straight ahead. Whats even worse is trying to back down a big hill that you didn't make. In that situation, there is very little weight on the front wheels so as you are backing down with the brakes on the front tires are skidding all the way. This can get you sideways on the hill very fast.