Forcus

My 90 TII with ABS has been sitting for more than 5 years. Got it started and running and only has brakes if I pump them 5-6 times.. then they bleed down. Would bleeding solve the problem or since it bleeds down is this some kind of intarnal leak?

Syonyk

Check for a fluid leak somewhere in the brake system. It could be a broken rubber hose or something. If there's no fluid leak, you're probably looking at a new master cylinder.

-=Russ=-

Snrub

iTrader: (1)

Brake fluid has a finite lifespan because it absorbs water. Slowly over time it works less and less. I'd say it's possible that you just need to change your fluid. Alternatively as has been suggested, obviously with 5 years of sitting something could have seized up and caused a leak in the system.

Forcus

I'm thinking it's the original fluid. I have narrowed it down to an internal leak or air/water in the lines. It does have a yellowish cast to it and I know that new fluid is clear.

I guess the main reason I was posting was because I wasn't sure if this was something that was easily solvable and may have something to do with the ABS unit. I have never worked on a car before with ABS so it's new to me.

Syonyk

Actually, new brake fluid is slightly yellow. At least all the stuff I've used is. "Old" brake fluid is an ugly brown/black, depending on how old it is.

-=Russ=-

WAYNE88N/A

Sitting for that long, the small particles in the master cyl fluid probably "cemented" themselves to the inner bore, so as soon as you actuated the cylinder again, the seals scraped over this gunk & destroyed themselves...

That, or the pressure required to "unstick" the caliper pistons after sitting in the same spot for 5 years killed your seals...

Forcus

Well after visiting 3 local chain parts stores yesterday (one couldn't get a master cylinder, one could in 3-5 days, and one could by Tuesday but gosh darn I'd have to pay ahead of time) I decided to try bleeding first before choking up $100 for a new MC.

Poured in some new fluid and started at the LR, good steady stream of fluid with some rust particles. Worked my way up, did the RF, then the ABS unit, then the LF. If it had a bad MC I was expecting a dribble but there was a pretty good stream in the rear and a definite high volume squirt in the front and ABS unit. However on the first stroke of the MC you could hear a "woosh" sound that went away with progressive strokes. Bad MC?

Good news is I got some braking action back. Before I would have to pump it 4 times and it would bleed down. Now on the first push, hard, it will get some braking action, second, more, and third even more but still not satisfactory.

My question now is should I continue to purge the old fluid since it seems to be improving? Or call it a day and order a new MC? I also noticed that the old brake pads seemed a little thin, I don't believe this should cause a pumping / bleed down problem but might be exagerated. Is the stock pad depth (not including the backing plate) about 1/2 inch? If I knew that I could measure it.

The only other thing I can think of is that the reason it gets better after three pumps is that the MC is weak and the old, original, rubber lines are swelled up / broken down on the inside so that with each push of the pedal, some fluid gets pushed to the calipers and when letting off the pedal, that fluid gets "trapped" by the old lines. Each push traps more fluid and allows the brakes to actuate. The problem is this is just a guess and the brakes do not drag.

Any help? Really don't want to buy a rebuilt MC if i don't have to. Not even going to bother calling Mazda. I bet they want $300+ for one.