[Airhead315]

Hey everybody,

I tackled the job of changing the brakes this weekend and ran into a considerable snag, I did the passenger side without an issue, when I got to the drivers side I found the pads on this side to be twice as thick, and when trying to compress the caliper piston I feel im putting way to much force on it...The seal that goes around the piston is also not where its supposed to be...is the caliper frozen? is that why im getting uneven wear? My calipers say ATE on them but there no spring clip...here are pictures for reference:

The pads on the left are from the passenger side caliper(compressed fine) The pads on the right are from the drivers side(wont compress without a TON of force)

This is the caliper in question. You can see the seal sitting out of the piston. If I was able to compress the piston correctly, that seal should sit itself back in place...

If this is a frozen caliper, do I need to replace both calipers?

Its a 1992 Saab 9000 CD Turbo.

 

[Saviour]

My advice....strip out both calipers, use WD40 to clean and unseize pistons, replace gaters and wash with brake flud, not a big job, just a pain.

Andy

 

[BOF]

I second Bacardi's advice. Almost certainly the piston in the right-hand caliper is almost completely seized, which would account for the (relative) lack of wear on the pads on that side. If I were you, I would put new seals in the calipers while you've got the pistons out. You will probably find it very difficult if not impossible to get the right-hand piston out of the caliper without damaging it with the caliper off the car, so before you tear it down, put the left-hand pads back in and push the right-hand piston out by pumping the brake pedal. Messy (when it comes out), but easy compared to trying to lever it out on the bench. And keep an eye on the fluid level in the reservoir - you don't want to let any more air into the system than you have to. HTH.

BOF

 

[Airhead315]

Ill be purchasing a new caliper on monday in hopes of recieving it on tuesday and installing it. So in order to prevent core charges, id like to remove the old caliper sunday/monday and not reinstalling a new one until tuesday. Is the brake system a closed system of hydraulics? In other words, can I remove the old caliper and let it sit without losing all the fluid out of the resevoir and ultimitaly making my have to bleed the whole system?

Thanks,
Aaron

 

[zeppelin]

you will have to seal the brake pipe or you will lose all fluid,put cling film with an elestic band around it to stop leaking. i would advise bleeding system once caliper is replaced.

 

[Saviour]

When Bleeding make sue you follow the Manual, They can be a SOD if you don't, and don't try doing it your self, an extra two guy, one pumping (some 9000's only need the fronts pumping, the rears just flow from ABS pump) the other keeping the reservoir toped up.
Makes life a dam site easier.
P. S. Use Copper Slip on the back side of the Pads, the Metal part and clean all moving surfaces, where the sledges slide, put a smear of C. S. here to. a bit of grease always helps movement.

20 mins per side, that includes removing the wheel.

 

[Airhead315]

Bacardi,

I plan on using a device called a "One man bleeding system" it basically doesnt allow air back into the bleed screw, its basically a plastic bag that you put fluid into, then you use a suction cup to hold it to the side of the car above the wheel, then you attach the end of the hose to the bleed screw, and voila...all Im supposed to do is pump the brake. Im not interested in doing a FULL bleed as I just had my clutch slave cylinder replaced and they did a full bleed with new fluid, I just need to fill the new caliper with fluid and remove and air.

 

[Saviour]

I plan on using a device called a "One man bleeding system"[/b]

GOOD LUCK..! I'm from the old school, don't relay on a 'GIZMO' to do the job.

 

[Airhead315]

Ill let ya know how it goes

 

[mark e]

In my experience you'll have great difficulty bleeding the system without using a pressure bleeder. The "one man" devices orginate from the days when cars didn't have ABS, and fluid would flow freely and naturally under gravity form the reservoir.

Gunsons make a handy device called Easibleed, which uses a spare tyre to pressure feed the system. It's easy to use and very effective.

 

[Paul Harrison]

You may have done the job by now but if not, put a brake hose clamp on the rubber hose before disconnecting the caliper from it. Mole grips are not recommended but I have seen them used by a garage. Do not remove the hose at the car body end. This should stop fluid running out and any air getting into the rest of the system. Also check the hose where it goes through the strut support looking for ballooning - if any found then the hose needs replacing (from my experience).

When you remove the clamp if the caliper is back on the body, do it whilst somebody is pushing on the brake pedal with the bleed nippple open so the air that has got in is pushed out instead of floating upwards. Could also consider connecting the caliper to the hose and holding it above the clamp, then slacken the bleed nipple, remove the clamp and if lucky, gravity will run fluid through pushing out the air. Still need to bleed once the caliper is on the car.

 

[Airhead315]

Ok, I put the new caliper on today and bled the brakes. The Pedal feels as solid as it did before I had any brake problems. But the brakes dont seem to have much stopping power at all. Its as if the pressure is there, but its just not gripping like it should be. The pads are new to my car, theyre used pads scraped off a car in the junk yard, there pretty much brand new. I know installing new brake pads causes horrible stopping power for the first 400 miles or so. Is this the time it takes for a pad to accept the rotor? or is it simply the time it takes for a new pad to get to the right material(in other words, should the car be stopping as it would with brand new pads that need to be worn in? or because theyre used should they be working fine from the start?)

Thanks,
Aaron

 

[Paul Harrison]

The pads will still need to wear in until their contact area profile matches that on the rotor (disc).

 

[BOF]

Airhead, if you used pads from a scrapper, they will have been worn into the discs on that car, and its discs won't have the same wear pattern as your discs. So effectively, first you have to wear the "old" wear pattern off them, THEN the pads have to wear into YOUR discs. They will do so eventually, but you might have the odd heart-stopping moment first! If you can run to it, it would be better to put brand-new pads on. Alternatively, be prepared to drive VERY carefully until the brakes work acceptably again.

BOF