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where is the air comming from?


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cox438
Novice

Feb 6, 2009, 9:34 AM

Post #1 of 4 (1235 views)
where is the air comming from? Sign In

Year of vehicle1998
Make of vehicle ( Chevrolet)
Model of vehicle ( Z24 Cavalier)
Engine size (2.4L)
Mileage/Kilometers 207000

98 chev Z24 clutch is showing no signs of leakage but is pulling air. Have to bleed system every 4 days. I Have replaced entire system from reservoir to master to slave 2 times and end up with same result works great for 2 months and then is back to pulling air. I even had trans shop do the second system replacement thinking I may have missed some thing but ended up with same result. Stumped on this one, any one know where to go from here?



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 6, 2009, 1:45 PM

Post #2 of 4 (1230 views)
Re: where is the air comming from? Sign In

I'm a little surprised it will work for two months and repeat the same problem! Were same brand parts used?

True - you really ought to be seeing a leak?!?!

Wild maybees on this: The flex hose might have a leak that holds pressure and not the slightest vacuum if it hasn't been changed I guess it needs to be ruled out. Lines must have a good fit. If somehow a line is close enough to very high heat such as exhaust parts then it might be boiling the fluid in the line unseen but they shouldn't be routed that close. Were any changed or replaced for any reason?

Not real sure?

T



cox438
Novice

Feb 6, 2009, 4:06 PM

Post #3 of 4 (1225 views)
Re: where is the air comming from? Sign In

Yes matching parts were used both times
After market first time and chev parts second time
have not replaced flex line well i didn't because It looked ok no leaks? Don't believe trany shop replaced it ether don't see the part on my bill. The lines are well away from any heat so i don't think it could be boiling.

I'm going to try the flex line like you say there may be a small pinhole causing air to be pulled in on the back stroke of the master plunger. I hope this is it but some how I doubt this is the problem.

If it still persists after this any other routs I could take?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 6, 2009, 4:52 PM

Post #4 of 4 (1222 views)
Re: where is the air comming from? Sign In

Flex hose:

Here's the deal with those. Used in brakes with more pressure and abuse IMO and they do get more attention in those. I wouldn't just toss one for the clutch but it probably is a good idea.

I've seen them just blow out and leak and be the whole issue with clutches but not act up as they have several times on brakes. What can happen is the flow can fail as it's layered construction to tolerate movement while maintaining integrity and not expanding much. In brakes the hidden flaw they do is make a "reed" valve effect such that fluid can pass one way but can't return - it's that layering that fails.

OK: Thinking (Caution when I do that!) It's still funky rubber product and just like a tire that will hold air when filled might leak or leak more when part filled - hair loss ensuesCrazy

Same thing in a way. The pressure may seal the flaw and slight vacuum due to temps, vibrations - whatever might allow air in to the system but doesn't allow fluid back out so goes unseen.

You answered my question about parts. Sometimes there's a whole string of bad parts if the same manufacturer was used with the same results you are allowed to question the parts even a second time. You used different makers of the parts I hope which pretty much rules that out - even at GM they might have sent out for aftermarket parts - who knows for sure if you don't ask you won't know on that but the hose needs to go at this point just for posterity now as this is too funky and predictable with it taking the four days to accumulate enough air to give you a problem.

I'm guessing of course but there is noted expansion and contraction of almost everything known when heated and cooled - the brake fluid in this is no exception.

LOL - ever use a drinking straw that had been bent/with a crack and it would work, not work, give you fits wondering what the F (that's FahrenheitWink) is going on? I COULD be the same crap!

T







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