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Discussion Starter #1
My co-worker came back from lunch and told me it was 70°F outside, so I finished up a few things and raced home to blow the dust off of my '86 Spider. When I parked her a couple months ago, she was idling roughly, on 3 cylinders. I changed out the plugs, turned the key, and she woke up refreshed! After an oil check and all-around once-over, I took her for a spin around the neighborhood. The first thing I noticed was that, while I had brakes, I did not have responsive brakes. Not good!!!

Once I got back into the driveway, I touched the discs and noticed that they were hot on both rear wheels, but cold on both front wheels. The brake fluid level is fine, and the master cylinder is new last spring.

Here's my question. It seems unlikely that both front wheels are siezed, and it seems that I'd notice a loss of fluid in the reservoir if the brake line to the front wheels sprung a leak. Might I have just done a poor job of bleeding the front brakes when I changed out the master cylinder? Is there something else I should suspect? I know I should look at pads, and I will, but I'm not sure I would know when pads are ready for replacement as I've never changed out a bad one.

Looking in the shop manual, there can't be much that affects both front brakes simultaneously. I'm hoping that the experience and wisdom of this community can clue me into what I should be looking at. I'll have a little time in the morning to look under the car, and hopefully I'll find that it's a simple fix.

Tim
 

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Did the front brake work before storage? (you know, did they act goofy then and mabe you just told yourself 'bah, I'll get it in the spring'?)

If they worked, then you may be able to get away with trying to free them up by levering the pistons back into their bores a little bit.

Be gentle, only go a little, then press the brake pedal to squeeze them back out, pry in, brake pressure them out, repeat a few times and you just might get lucky and they'll start working properly once they free up.

No promises, but it has worked in the past.
 

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Discussion Starter #3 (Edited)
I suppose that I need to figure out if my calipers are frozen or if they're not getting any pressure from the master cylinder. My shop manual doesn't seem to indicate anything about that. I have the one from IAP. Is there another, better, manual for this sort of stuff?

Hey Tifosi, how far upstate are you? My home town is Oswego. I hear they got hammered this winter.

Tim
 

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Discussion Starter #4
Well, the pistons seem to be doing their job in some sense. On the driver's side, I forced the pads all the way out and then stepped on the brake pedal. I could hear the pads getting pushed back in by the pistons. I looked at the pads, and they seemed to be thick enough, so I tried bleeding the front brakes. Here's where it gets interesting.

I'm using a hand-operated vacuum pump to draw the brake fluid out, rather than pumping the pedal, since I don't have anyone around to help. The passenger side front brake bled just fine. On the driver's side, however, I seemed to keep getting an accumulation of bubbles whenever I drew brake fluid. I ran about 6 ounces through, even messed with the hose connecting to the end of the bleed valve and the valve itself to see if air might be getting in that way. It seems that I'm drawing air through a leak. But I'm not losing fluid through the lines, as far as I can tell.

Just a wild, uninformed guess, but I'm suspecting one of the pistons. Could I be drawing air through the system but not pushing out an appreciable amount of fluid? My pedal doesn't sink to the floor, but it doesn't pump up very high either. I'm not very experienced with car mechanics in general, so this has me a bit stymied.

Tim
 

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Two possibilties. One is that the rear brakes are dragging - the brake pistons not retracting. OR the front brakes are not activating - brake pistons siezed. Or both...

Have you (ever) flushed the hydraulic fluid? DOT 3&4 brake fluids are hygoscopic - they absorb moisture, even water vapor from the air. Over time this water degrades the fluid's performance and will allow corrosion. The brake fluid should be flushed every 1-2 years.

Here's what I'd suggest. Jack up the car and remove the wheels. Remove the brake pads - making note of where they came from (so you can return them to the same spot if they're going to be re-used). Do this one caliper at a time. With the pads out (one wheel at a time), have a trusted assistant slowly press down on the brake pedal while you watch the brake pistons in that caliper.

Normal action is that piston will move out as the pedal is pressed down and then slightly retract when the pedal is released. The only thing that encourages the pistons to retract is the slight distortion of the rubber seal surrounding the piston. (i.e. there is no return spring)

If the piston is cruddy (technical term for dirt/corrosion/crud) it can either stick in the caliper (brakes don't apply) -or- not easily retract (brakes drag).

What you need to do is get your assistant to press down on the brake pedal enough to push the pistons out about 1/4" and then use a strip of rag moistened in brake fluid to clean off the cruddy stuff. I use a strip about 1/2" wide and a few inches long in 'shoe-shine' fashion.

Once clean, press the pistons back into the caliper and then have your assistant press down on the pedal again to 'exercise' the brake. One or two of these exercises (after the piston has been cleaned) should get the brakes working again. Repeat for all four brakes.

Then get a large container of new brake fluid (DOT4 is advised). Open the bleed screw on the left, rear caliper, attach a hose to the bleeder's nipple and aim the hose into a container to receive the old brake fluid. Have your assistant press down on the brake pedal and you'll begin pumping out the old brake fluid. Do this for 3-5 strokes of the pedal then check the master cylinder. DO NOT let the MC run dry - that'll allow air into the system which can be a bugger to expell. When the MC is low (but not quite empty) fill it up with your new brake fluid. Flush again until you're pretty certain that the old fluid has been flush out. Then repeat with the right rear, then right front and left front.

BTW, I've seen it advised that the system should be bled diagonally, right rear and left front together and left rear and right front together.
 

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Discussion Starter #6
I just had another thought... how thick are the pads supposed to be when they're about shot? Might I be getting air into the system because my caliper piston is over-extending on the driver's side?

Tim
 

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Discussion Starter #8
Eric, thanks for the insights and instructions. I guess I need to figure out how to remove the brake pads and get them back in again. The instructions in my shop manual are pretty sparse.

I did flush the system last year when I changed out the master cylinder. I used DOT 3 because that's what the printing on the MC reservoir says. My logic to bleeding the system is to start with the wheel furthest from the MC and work toward the MC. Could that be a problem? The front and rear systems are independent of each other, so it doesn't seem like it would be.

Ah, an assistant. The one tool in my drawer that seems to be missing right now. Actually, I do have one, but she's an hour away and it's my weekend to visit her.

Tim
 

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Discussion Starter #9
Okay, this is a really basic question. How do I know when the pads are worn out? I need a basic auto mechanics course!!!!

Tim
 

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Front and rear pads that are at or under 7mm ~ .28" (a scosch over 1/4") thickness on the friction surface are considered worn out to the point of replacement.

If they are really shiny and glazed look regardless of thickness, they prolly need swapping also.

Any cracks at all and you need to get them off your car.


To remove the pads, get the wheel off and using a small non-tapered drift (or a big nail with the point ground flat) drive the two pins you see going through the top of the pads through the little loops from the outside in. (as in put your punch on the outside)

Once you get the first one out, the cross shaped spring in there will generally pop up a bit. Keep track of it when you do the second pin.

Once both pins are fully out, you 'should' be able to lever the pistons back in their bores and just slip the pads up and out through the top.

'Should' is relative.

Sometimes the wear pattern or depending on if goo was used to stop squeeks causes the pads to seem like they're all but welded in.

No worries, just use a lever through the loophole in the top (switching from one to the other to 'walk' it as the pads have to come out pretty straight) and work the pad out, or, if it sitcks up enough, grab onto the loop (again, switch back and forth) with a decent set of channel lock pliers and tap them upward with a hammer. (or vice grips and lever against the vice grip)

Reassemble in reverse order, hooking the cross shaped spring under the first pin before you send it the rest of the way through it's other hole, then go for the second pin. (don't forget the pins will be going in from the inside out)
 

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Silly question, but with you mentioning the rear rotors heating up......


Did you happen to have the P brake set all winter?

If so, are you sure it released fully? (real wheels up off the ground and they spin freely)
 

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Okay, this is a really basic question. How do I know when the pads are worn out? I need a basic auto mechanics course!!!!

Tim
You should have about 1/3" or 8-10mm friction material left on the pads.
But even though you have less than that the cylindres in the calibers should not draw air in.
Clean up and massage the pistons as described, if this doesn't help, you need either a proff. Alfa mecanic's help or new calibers at front.
Erik
 

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Hey Tifosi, how far upstate are you? My home town is Oswego. I hear they got hammered this winter
From Oswego, about 70 miles north by northeast in the Watertown area.

Hammered?

I wouldn't say so, or at least we didn't get any more than our usual 10 to 14 feet. :shrug: (I used less than 5 gallons of gas in the snowblower this year if that helps, though there were a few times where I was out moving snow 2-3x in a day, but that's not terribly uncommon here :) )
 

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Discussion Starter #14
Okay, it's all starting to make sense to me, now. Thanks Eric and Tifosi. I'm going to go ahead and put the front up on stands pull both wheels and pads, and see what I have. I'm pretty sure the fronts need replacing, and that might be the extent of it. It's going to be 75° tomorrow, but I won't succumb to temptation. Slow braking is not a good thing!!

Tifosi, I reread the service manual after your explanation and a peek at the calipers, and it all seems pretty easy now. I'm sure the pads are shot, and were probably gone last fall, but I didn't notice it because the change was gradual. Rotors are scored, and might be good for a replacement.

Off-Topic: I remember plenty of winters with 12+ feet of snow, but my dad said it was over the course of 2 weeks this year. I think that qualifies as one of the more memorable winters!! Dad never owned a snowblower--he had two kids and plenty of shovels. :)

Where I live now, we generally don't get more than 1 snowfall per season, and usually just a few inches that lasts a day or so. The county was shut down 2 years ago when 22" fell in 2 days. I couldn't climb the hill at the end of my driveway until it melted because plows are almost non-existent around here. I calculated that I hand-shoveled 6 tons of snow to clear my 350' drive to the road, moving about 1 ton per hour. Body was a little sore after that one--I'm no athlete!!
 

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Discussion Starter #15
Wow, what a difference an hour makes! I picked up a new low profile floor jack and a couple of stands today, and popped the front wheels off my spider as soon as I got home. With Tifosi's description in mind, I easily slipped out my pads. I pressed the pistons back into the calipers before removing the pads, so that it'll be easier to get the new pads in. I've got less than three millimeters of surface on each of my pads. That certainly explains the braking problem! Parts are ordered, and I'll inspect the calipers before reassembling.

I can't believe how easy this has been. I guess it's only mysterious when you haven't been through it before.

Tim
 

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And here you were all worried. Piece of pie, inni't :D (I do mine a couple times a summer for inspection purposes as I am apparently a bit hard on the equiptment, though I'm getting almost 2 summers out of a set of pads now so I guess that means I'm improving.....)


Might better get the rotors turned or at least scuff them up real good before the new pads show up, otherwise you prolly won't like the way the new pads work even if the pedal is firmer and higher.

Turning entails removing hub w/bearing on the front.

Getting it apart isn't so bad, and it's a good excuse to examine, repack, or replace if neccisary the wheel bearings and inner seal.

The tricky part (well, not really tricky, but you have to pay attention) is getting it put back together with the proper preload and whatnot on the hub nut. (and remembering that the left spindle has left hand threads)

The rears (if your doing them at the same time) have just a couple screws holding the rotor on. (they are easier to get off because they cost more to get turned what with the P brake 'drum' built into the inside of them)
 

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While not your problem, it's a good idea to pump the brake petal (like 10 times or so) every few weeks (or at least monthly) during winter storage to give exercise to your caliper pistons and seals.:)
 

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Discussion Starter #18
Good tip, LowMileage! As a matter of ritual, I make sure I take the Spider out for a romp at least once a month in the "off-season", since we usually have some good weather for it. The brake pistons need a little exercise, but a good, all-around cardio workout is even better!!! :)

This time, though, I let it sit for about 2 months because the engine was running a little rough when I last turned her over in January, then we had the coldest February I've seen in the last 10 years. The heat bill was a shocker!!
 

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Discussion Starter #19
Tifosi, Good advice on the rotors. I figured that the pads were so easy, I'd save the rotors for another weekend. I may put new ones on, and have the old ones turned for back-ups. I do have one piston seal that looks like it needs replacing, so I ordered a rebuild kit for the fronts. After a test drive, I'll take a peek at the back brakes as well.

Tim
 

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Discussion Starter #20
Well, life is good again. I got the new pads installed last night, cleaned out my vapor separator, changed the gasket on the oil cap, tightened up the bolts on the exhaust manifold, and took my baby out for a couple of nice rides.

Alas, I still have oil leaking from the driver's rear corner of the head, so it looks like I'm due for a head gasket. I'll try retorquing first, but I'm not expecting much. But if I have to pull off cam cover and the intake plenum, it'll be a good time to replace motor mounts and check my cam clearance.

Geez, one simple brake job and I've got a mountain of confidence!!

Tim
 
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