Aspire Brake Woes

[Nerd Racing]

Hookay so here goes:

I took my car to get inspected and they said I had a leaking caliper piston. Being close to the holidays I decided to rebuild it instead of replacing it. All that went well but then when I went to bleed the calipers the bleeders broke off. I bled it by the lines and the pedal seemed super stiff like normal before the caliper started leaking.

Until...

I started the car and now it goes halfway down and does not get hard till I pump it and still isn't that stiff. I went around and re-bled the system back to front and it seemed to be better but now its back to having to pump it up to stop. The thing that gets me is that its rock hard till I start it, then its spongy.

I'm not leaking any fluid, or at least not a noticeable amount by the reservoir level.

I'm thinking replace the caliper? Might upgrade to EGT/Protege LX/MX3 GS/4WD Protege Calipers.

[crazyrog17]

something's telling me master cylinder/brake booster. check to make sure nothing's leaking under the hood when you start the car and press on the brakes.

my cousin's truck had the same symptoms and when he pressed on the pedal, brake fluid shot out HARD from between the cylinder and booster.

[Nerd Racing]

its not leaking any fluid, fill level does not change.

[DrMaxwellEdison]

just wont let ya stop?

[Nerd Racing]

pretty much, if I pump it up it stops... sounds like air in the lines but I've bled it well, except for the no bleeders in the front. Might swap my 4wd pro's calipers on there tomorrow.

[Damkid]

If you have the spare calipers to swap, I would try that first, but I had the same symptoms with my green festiva and it was the master cylinder that was bad

[scitzz]

When you say bled it by the lines, did you loosen the brake line at the caliper?

[1988festivazoom]

It seems like that's what he meant.... but that's a verry in-efective way to bleed brakes bc your not forcing air from the actual caliper, your just wasting brake fluid. Go to the "dorman" section of your parts store and get some new bleeders and a "easy out" and replace your bleeders. That's the only way to properly bleed them. There is a reason for placment of the bleeders on the caliper.

[Safety Guy]

My guess is that since the brake lines are lower than the bleeder screws, you are not getting out some air trapped above the brake line. In other words, air in the top of your caliper reservoir. I'd fix the bleeder screws or get new calipers with good bleeders.

Keep in mind I'm not a "real" mechanic, car tech or brake designer. So I'm not sure about this but that's my guess. I've never cut a caliper in half or seen a cutaway diagram. Maybe it doesn't work that way. However, I do know that air will want to rise in a fluid, so the air should try to go "up" and if it does, you won't get it out by bleeding at the brake line. What I think happens is that your hydraulics are all fine until the pressure tries to build in the caliper top section. If there's air in there, then it compresses (gas is compressible while liquid brake fluid is not).

I bet the brake bleeders are placed where they are so that they will get all the rising air in the lines to exit at that high point.

Karl

[Safety Guy]

I googled "brake caliper cutaway" and I got one!

AZone has two pics showing the internal "channel" from the piston reservoir to the brake bleeder plain as day:

http://www.autozone.com/autozone/repairguides/Volvo-Coupes-Sedans-Wagons-1970-1989-Repair-Guide/REAR-DISC-BRAKES/Brake-Caliper/_/P-0900c15280064524

Click on the tab under either pic for a much larger version.

The pics don't show the brake line entrance though. However, the bleeder screw is higher than the brake line entry, so I do think some air is trapped up there and won't be purged by loosening the brake line nut. I wish the cutaway showed this area, but it doesn't.

Karl

[WmWatt]

I broke a front bleeder nipple when replacing my brake lines and did what you did, bleeding from the hose connection. The extractor didn't work. It's still in there, broke off. The brakes work fine.
You might have some air in the caliper but not necessarily. It would depend on what you did after the nipple broke. I did not disconnect the line until I gave up on the nipple extractor so no air got in.

[1988festivazoom]

Try harder to get it out lol or move to oregon where they don't salt the roads so your poor little tin cans don't rust! Mine is 100% rust free.