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Wheel Cylinder Q. (See last post)

MC & Brake Booster

I am guessing it keeps dust out & NOT fluid in, so gonna say NO!

I am wrong on occassion though.

Bucky

712edf wrote:I am guessing it keeps dust out & NOT fluid in, so gonna say NO!
am wrong on occassion though.
Bucky

I have no pressure when I push on the brake peddle. When I replaced the master cylinder, the only thing left out was that seal/diaphragm thingy. I don't recall if the original one had this seal or not. Also doubt that it has anything to do with fluid, but probably more than just dust since it has a hole on the end that would seem for the push-rod to go through. Maybe it is needed to seal air in the brake booster. Inspected brake lines for leaks, but found none.

have you tried to bleed your breaks or flush your entire brake system out?

Did you bench bleed the master?

Keeps dust and grit from eating the mc end bore/seal as quickly. My truck had a center bolt master when I got it, swapped it for a bail type that never worked properly. Now has a center bolt type again. Took a couple months for all the micro air bubbles to work there way out. Let it sit for about the last 3 weeks and now the brakes are perfect.

My motorcycle is the same way, I have to let the trapped micro bubbles come to the top on their own accord before the brakes work right. Even back filling doesn't do it. There must be something in the hard line spiral that doesn't let it bleed correctly.

I never bench bleed the MC.

I tried to installing the MC onto the brake booster with the seal thingy on, but there is no way it fits.

I did flush the lines using a one-man bleeder. Although I watched to see if was taking in air (flowing the wrong way), it may have taken in air through a bleeder screw where it threads into the wheel cylinder. Maybe I'll stick with the two man operation.

reallylongnickname wrote:I never bench bleed the MC.

You should.
John

I tried to installing the MC onto the brake booster with the seal thingy on, but there is no way it fits.

I'm guessing that rubber boot would be for manual brakes...they wouldn't require that boot when attached to a brake booster.
Just my

Yeah, mine has manual brakes.

Pop it back off and bench bleed it or do an on truck bench bleed. Either way, throw away the cheesy little plastic fitting from the kit and go buy some barbed metal ones. Metal will seal, plastic threads are likely to strip. Kit for mine came with one bleeder plug the wrong size.

I bench bled the master cylinder, but still same result.

Today I pulled off a wheel and drum to have a look. Every thing was dry. I looked behind the rubber on wheel cylinder, and discovered about half a teaspoon of fluid on each end.
Should it be perfectly dry or is this normal?

Today I pulled off a wheel and drum to have a look. Every thing was dry. I looked behind the rubber on wheel cylinder, and discovered about half a teaspoon of fluid on each end.
Should it be perfectly dry or is this normal?

I'm gonna guess that it's not normal.

they should be dry in there the cups are leaking. probly better to but the whole new ones they seem to be same price or cheeper then kits if they are available. and when you done you may need to gravity bleed the system if the truck hasnt had any brakes in awhile. specially on a man system

daytb wrote:they should be dry in there the cups are leaking. probly better to but the whole new ones they seem to be same price or cheeper then kits if they are available. and when you done you may need to gravity bleed the system if the truck hasnt had any brakes in awhile. specially on a man system

My theory is that, in the process of remanufacturing these wheel cylinders, when they hone them out, they are actually slightly boring them and then adding the original size seals.
That or possibly the seals are being pushed out too far even though the pads are new. Anyway, thanks. I will replace the rear ones and have a look at the front ones.

If you have a Parts Plus in the area, the cylinders run $10 each, NEW. I've gotten them NEW from Autozone as well, $12ea, no core required, but they are made in India and might last a year. Maybe. If you are lucky and don't drive it very much.

Got new rear cylinder and front drums from NAPA for the cross country move, cylinder and drums are thin Chinese made junk.

welll good luck

Rebuild kits for the wheel cylinders are about $2-5 each. Got to make sure there is no corrosion on the ones you are rebuilding if you are concerned with the quality or price. Gravity bleeding works great by the way........

I still have a soft brake issue and I'm looking for feedback plz before I dish out $ for more parts like a brake booster. Today (July 10th) I tried a 2nd master cyl but the result was the same. Here is the brake down on what I've done so far:

• -replaced all four whl cyl with new ones
  -checked for leaks in brake line
  -replaced master cyl -bench bleed both mc