How often do you guys replace wheel cylinders?

I changed my friend Dave's front brake shoes 3 weeks ago and yesterday his right front wheel cylinder blew. Drained the reservoir and soaked everything under the drum. It's a '68 Dart 4-door with 10" drums (it's a 273, not a slant). Fortunately he made it home OK.

When I changed the shoes last month, I checked the cylinders for leaks and they were dry. The cylinders looked old, but since they were not leaking so I saw no reason to replace them. Was I wrong in thinking this?

Dave has had the car for about 4 years and never replaced the cylinders, so we don't know how old they were. They may have been the originals from '68. When I bought my '66 Dart, I replaced all front brake parts since I didn't know their history. I'm thinking I should have done this for Dave, too, and in the future I'll be more aggressive about replacing old brake parts.

I'm also curious if my working on the brakes might have prompted the cylinder failure. Perhaps when I was installing the shoes, I pushed the pistons/seals beyond their usual travel within the cylinder and they encountered some crud or rust. There was a lot of nasty stuff in the old fluid. I flushed it out, and I'm going to replace the other cylinders ASAP. The hoses look OK - no cracks, and they appear to have been replaced not too long ago. Should I consider replacing the master cylinder, too, or is that overkill? I've already replaced the blown cylinder and the fluid-soaked shoes, and the brakes now feel fine.

Anyone have any opinions about all this?

Thanks,

Steve

Hindsight is great isn't it.......

If I don't know how long the cylinders have been there, and am overhauling the brakes on an old car, I'll replace the wheel cylinders.

With my truck I replaced them at 15 years cuz I was changing the original shoes before a cross-country towing trip. Think if there over 10 years I'd replace them if doing shoes.


With the master cylinder, if it's an unknown, i'd probably replace it if I was replacing everything else.

However, I'm one of the few people that actually replace all the brake fluid every once in awhile, so if the master has been with me the whole time (either I bought the car new, or previously replaced it) I'd wait for it to actually fail. (Not so sure about waiting for a single master to fail though..........)


As for the failure, you're right. When working on brakes, you usually get the wheel cylinder to function in an area that wasn't in use (the piston travels in an area where crud and dirt has accumulated) thus it messes up the rubber cups.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

steve;

on old cars, brakes should be considered top priority and assumed ready to fail at any moment unless you know for a fact the part has been replaced or rebuilt recently.

that is definitely erring on the side of caution, but no matter how much go you have....no 'whoa' causes a LOT more of a problem.

sb

A couple of years ago I replace the right rear wheel cylinder because it was rusted solid! Cause? One of the plugs was missing on the backing plate, allowing water to get into the brake assembly. The funny thing is, I flush the brake fluid twice a year to keep things clean and get moisture out of the lines. This last summer I rebuilt the fronts. I replaced them (along with the rubber lines) when I bought the car in summer of '97. With the twice yearly flushes, they where in very good shap with no scoring or corrosion, just some seeping around one of the rubber cups.

I have drums, period! With all the new technology out now, why not upgrade to disc? They stop sooooooooooo much better than drums. Unless of course your doing it on a budget then the point is moot.

Hey Folks,

How do you flush your brake lines? Just keep pumping the fluid through with the brake pedal until it comes out clear? Or is there another way, like a power bleeder?

-Mac

I use speed bleeders. They have a one way valve in the bleeder screw so that once fluid is pumped out, air can not be sucked back into the system. The ones I use are made by Russell. http://www.russellperformance.com/auto/ ... ders.shtml You can also find them in the Help section of an auto parts store.

I made some speed bleeders................


Wrap teflon tape around the threads of the existing bleed valves (so air doesn't get sucked it, also keeps them from rust welding.)

Get an aquarium airline check valve (the rubber flapper kind, not the one that's spring loaded)

Pump away (and don't forget to keep pouring brake fluid into master cylinder)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

vaccum line checkvalves from carbureted hondas work well too. i think gm used similar deals on 80's carbureted vans. these are the things that look like a little plastic drum placed inline in some of the thousand yards of vacuum hose on these vehicles.

-james

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