Are Brake & Clutch Cylinders maintenance items?

It's time for my 2year brake fluid on my '01 Jetta.
At 15 yr old, and 250K miles, should the brake and clutch master / slave cylinders be replaced? Or do the cylinders' seals have a much longer (average) lifetime?

Thanks, Glenn

With clean fluid, you will very rarely (if ever) see one fail. I wouldn't replace the cylinders unless they give you a problem.

Those items tend to be replaced on an as-needed basis. You're doing the best thing you can do to extend the life of the components which is changing the fluid regularly. The water that brake fluid absorbs causes rust and pitting to occur inside cylinders and lines leading to premature failure. Keep an eye on the dust/dirt seal around the piston on your calipers as their integrity prevents excess moisture and road salt water from entering the bore, leading to pitting and premature failure of the seal. You know you need to replace a caliper when it is wet with brake fluid around that dust/dirt seal. The master cylinder gets replaced when you steadily press on the pedal and it slowly (or quickly, if it's really bad) drops to the floor.

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I still have original clutch master, slave, and brake cylinders in my wagon at 14 years old and 334K miles. Original brake calipers, too. So far, so good.

My original stuff went out at around 240k miles. The master cyl started leaking fluid into the booster and when it killed the booster diaphragm is when it all got replaced. Booster is a nightmare of a job compared to just the master tho so if you wanted to change it as a precaution to save the booster you could. But than it would be more a preventative maintenance


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Bleed the clutch

Is there a bleeder for the clutch cylinder?

wonneber said:

Is there a bleeder for the clutch cylinder?

Click to expand...

Yes, on the slave cylinder.

I don't replace them preemptively replace them but I have had one go out on my BMW and that was an expensive PITA to have it towed to a shop and replaced rather than simply doing it in my driveway at time and parts sourcing of my choosing.

A couple years ago my wife broke the clutch fork on our ALH but, again, she was a few hundred miles from home so she had to tow it to the nearest reputable shop. It took a bit of talking them into but I finally got them to swap the DMF out for a Southbend stage 2 but they wouldn't budge on reusing the slave cylinder. The shop basically told me they had just had too many old ones either go out too soon or leak into the tranny ruining their job so they would rather not have to deal with the callback. I had her collect all the old parts, take pictures of the flywheel and clutch (we thought the clutch had gone out until they opened it up and found the snapped fork) and it seemed to be fine when I got it in my hands (albeit old and cruddy looking).

Anyway, they didn't charge me extra labor and my wife brought them all the non-aftermarket stuff (fluid and slave cylinder) from the dealership so they weren't trying to gouge us on anything. Just relaying what someone with more experience than I have explained to me and how he handles it. I wouldn't crawl under there and do it for fun, but if you were going to change out the clutch then it seems prudent to throw the $60 dollar part on there and call it good for another 200K+ miles.

We do hear from a few customers that their older slave cylinder fail after replacing the clutch. That shop's decision may make sense, and I would have gone along with it especially if the shop wasn't local. Returning to correct a clutch install error would have been a pain.

Clutch slave and TO bearing should be replaced with the clutch, just like doing a bushing inspection with a fluid/filter change or replacing the timing belt tensioner and idler "while you're in there."

Brake master should be visually inspected once in a while, just to make sure nothing's floating in the fluid. Most major issues here happen instantly and at the worst possible time, but a difference in pedal feel might warn you in advance once in a while.

Biggest thing with brakes is to have someone pump them a couple times, then stand on the pedal while you check the rubber hoses for bulging.