Ceased brakes, need help!

[scarzan48]

I have a '77 280z, previously the car sat around for about two years without being moved or started. I got it running again about three months ago with a couple fixes and got the brake fluid flushed in the process. About two weeks ago the brakes ceases up on me when I was driving around. It happened pretty slowly, it wasn't an abrupt stop. A couple days ago I replaced the calipers and pads in hopes that would fix it. Now I'm getting almost no pressure at all. There are no leaks in the lines that I can tell. Did I mess something up or am I missing something?

[d240zx2]

Could be air in the lines. Bled properly, new calipers should provide good braking.

Start your bleeding process from the left-rear, then right-rear, right-front, then left-front.

And make sure your master cylinder has been bled properly, too.

[mlc240z]

Also make sure when you replaced the calipers, you didn't swap sides.

The bleeder valve should be at the top of the caliper.

[Zed Head]

I have a '77 280z, previously the car sat around for about two years without being moved or started. I got it running again about three months ago with a couple fixes and got the brake fluid flushed in the process. About two weeks ago the brakes ceases up on me when I was driving around. It happened pretty slowly, it wasn't an abrupt stop. A couple days ago I replaced the calipers and pads in hopes that would fix it. Now I'm getting almost no pressure at all. There are no leaks in the lines that I can tell. Did I mess something up or am I missing something?

You said that your brakes seized (ceased up) as you were driving and then mentioned a slow stop. Do you mean the brakes locked up on you? Then you changed the calipers and pads, now you have the opposite problem, no brakes?

Can you pump up the brakes and get them to work, or does the pedal go to the floor and stay there?

If it worked for three months things must have been right for a while. More clear details on the history from when it worked to now would be good.

[scarzan48]

When I first got it running the pedal would be about to the floor, but after driving it a couple times the pedal came back, I assume it was mostly rust collection. I got the fluid flushed and they worked fine for about two months. The day it happened I was just driving around and after about 10 mins or so I started to smell the brakes but it was still running fine. Slowly the pedal started getting harder and harder until finally when I let off the gas pedal the car would come to a stop almost immediately. When I pulled over they were smoking and car could barely move. After I let it sit for about an hour or so the pedal felt a little better and the brakes had released a little.

[scarzan48]

I appreciate all replys, sorry if the descriptions are lacking good detail. I've never done any extensive work to my car by myself so it's kind of a learning experience.

[mlc240z]

Just to be sure, you did bleed the brakes when you replaced the calipers?

If you didn't, follow d240zx2's advice and bleed them.

If that doesn't solve it, might have to check your master cylinder. If you suspect rust in the system a rusted MC bore could chew up the seals.

If you're relatively new to working on cars, PLEASE either hook up with someone more knowledgeable or take it in to a shop. Brakes are way too important a system to guess at or use as a learning experience.

Not meant as a knock, just would hate to see you or someone else get hurt from not doing it properly.

[Zed Head]

The original problem, where your brakes slowly locked up, sounds more like a master cylinder or brake linkage problem (from what I've read, no first-hand experience). The master cylinder piston has to come back all the way to open the passages to the reservoirs. If it doesn't, when the fluid heats up and expands, pressure will build up in the lines and apply the brakes without pushing on the pedal. I might be wrong but this is my understanding of what could happen.

Something might be stopping the master cylinder piston from retracting fully. You didn't adjust all of the play out of your brake pedal did you?

So even if you do get the brakes to work, the original problem might come back if you have not done anything to the master cylinder or linkage. You should look at everything from the pedal adjustment to proper bleeding of the lines. The FSM has all of the details.

Edited June 29, 2010 by Zed Head

[scarzan48]

Trust me, I understand that I'm a noob when it comes to hands on working on cars. That's why I usually have mechanically educated friends work on them. At this point I'm just trying to get advice to see if I would even want to attempt to fix it, otherwise I'll let someone else do it. And I did bleed the brakes but only the front, I was told today to go ahead and bleed front and back, but I'll go ahead and get that done somewhere else. Once that's done I'll let ya'll know what happens.

[mlc240z]

Smart man.

Learned most of what I know watching my Dad work on the cars. You'll gain confidence the longer you work on 'em.

ZedHead has a good point.

If MC is FUBAR, could have caused initial problem and then shredded piston seals to cause second.