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196 Posts
I know this won't be earth-shattering for most denizens here, but it's useful to me to have a reference like this, even for things that are for most considered to be basic. In case it's useful for someone else some day....
And, question at the end.
The right rear brakes on the 1985 900 T16 could no longer be ignored. Because this is why:
https://vimeo.com/162214184
And that's after the caliper has "relaxed" a bit. The grinding was SEVERE, interestingly more so after /releasing/ the brakes. Just as interesting (to me, at least) is that the onset of this issue was pretty short. It went from "okay" to "DEATH TO ALL KITTENS" in a couple days.
Before starting I made sure to chuck the wheels & follow basic safety. Jack the car up, use a stand, don't leave it on the jack, keep kangaroos off at all times. You know, the basics.
After removing the wheel and carefully setting the nuts aside where they won't get Ralphie'd...
![]()
Then it went a little something like this:
![]()
Like a record, baby. But in a way that is NOT good.
I sprayed the caliper bolts and the heads of the two screws that hold the disc to the hub with Liquid Wrench and let it sit a while. That's the liquid visible on the concrete in later pics.
Removing the Caliper:
0) Under normal circumstances, a brother would be advised to pinch with vice grips the rubber brake hose that is behind the spring & shock in order to prevent fluid running all over the place. There are two of them, and it only takes a little bit of science-y eyeballing to figure out which is which. It quickly came to my attention that the hose is old and decrepit, pinching it might break it, and that was not an option. (Fast-forward to the end of this post if that bothers you as much as it does me) So....
1) Using an 11mm wrench, loosened the brake fluid line that enters the back of the calipier. Using speed & dexterity, as I pulled it out I quickly capped it with the bleeder valve dust cap. I lost a little fluid, but not much at all. Victory.
2) Using a 19mm socket (and preferably a nice, long ratchet or breaker bar, for leverage) the two bolts that hold the caliper to the hub were loosened. I switched over to a ratchet once I broke them loose.
![]()
Removing the caliper bolts with a 3/4" SAE nut. I cannot readily explain why I wasn't using a 19mm. Either way, worked fine. It took quite a bit of pressure to crack them loose with my short breaker bar. After that the bolts came out as easy as (having someone else bake me a) pie.
*NOTE*: Spanning the distance between the two bolts is a sort of washer/shield-esque piece of metal. There are tabs that are bent up flush against the sides of the nuts. These are presumably to prevent the nuts walking loose during operation. Some clever prising with a flat-tip screwdriver was all that was needed to shift these tabs out of the way so that the socket (or wrench) will fit.
Or in my case, they had been bent away and back before, and they just broke off. So, yay. Don't worry, I'll be back in here before too long.
But... how important are these little tabs?
3) The caliper came off pretty easily, just slid it off the disc.
4) Using a large cross/plus/phillips head screwdriver, I removed the two screws that hold the disc to the hub. To break them loose, I sharply rapped the handle of the screwdriver. They came loose easily enough, just a bit of wrist.
5) With a hammer I reached around and banged the back of the disc (at the "hole" left by the removed caliper) to loosen the hub. Again, it came off easily enough - just a few raps while turning it.
Now for cleaning & re-assembly.
![]()
ACDelco 18A83A Advantage Non-Coated Rear Disc Brake Rotor
Raybestos PGD21 Professional Grade Organic Disc Brake Pad Set
Dorman H100783 Rear Brake Hose
ACDelco 18K388X Professional Rear Disc Brake Caliper Hardware Kit
a pair of 10mm @1.0pitch x 20mm bolts to use as brake line plugs
a wire brush to take off crud
*NOTE*: These are not endorsements or even recommendations. They are just what I used. FWIW, all parts went right on no problem, nice fit.
![]()
Very much in the way of crud. Note also that the rubber dust covers are mangled. In fact, once the very stuck pads were pulled out, one could see that they were in fact doing more harm that good since a large section of it had split away and become lodged firmly between the piston and the pad. Given that I'll be back in here pretty soon, I though it best to just remove the rest of the cap to prevent it becoming wedged in again (and applying a camber to the pad).
Pad removal: they are held in with two pins. Using a small punch or even a medium-sized nail, tap them out with a hammer.
![]()
These calipers will have to be replaced, or the pistons therein will have to be rebuilt/repaired; and I will just as soon as I can afford the parts. This had to be done *now* because the caliper was not releasing fully and the grinding was Mordor-ific.
The brake fluid inlet was plugged with a screw to keep bits of crud from falling in during cleaning. Much brass brushing and degreaser later, the caliper was ready to be loaded with its bits.
The pistons were quite easily compressed using a c-clamp (making sure to release the bleeder valve first. Squirt squirt.)
Adhesive-backed anti-rattle/squeak shims are carefully stuck to the backside of the pads (on the face that contacts the piston).
![]()
The box came with a packet of silicon grease for lubricating slide contact areas, so, where the pad slides against the caliper, and between the caliper and the piston, and along the pins which hold the pads in place. I used an old toothbrush to apply the grease evenly & without overgooping.
![]()
The prepared pads are then placed inside the caliper.
I used a small spot of anti-seize goop on the screws that hold the disc to the hub. Nice and tight with the screws, but careful to not strip. Neighbors might see, that'd be no fun.
Since I was sure to compress both pistons fully, with the new pads in place the caliper easily slid over the disc.
Again with the anti-seize goop on the bolts that hold the caliper to the hub. I don't have a torque wrench (yet!), so I just made sure I turned them good and HARD - again, not so much that they will strip, break, or round the heads. I'd rather these not come loose.
![]()
Shiny.
Note anti-seize goop for lug nuts. Probably should have put that on after the wheel, but I was careful. No probs.
Test drive says, NO MORE GRINDING.
I'll be back in, though. Because:
Calipers rather urgently need reman or replace.
AND
HOW do I get the old rubber brake lines out? The ends that mate with the metal line are obvious, but I didn't see where to put a wrench on the ends that mate up to the body. And, is there a decent way to prevent fluid going everywhere? Or is it another quick & dexterous remove & plug?
And, question at the end.
The right rear brakes on the 1985 900 T16 could no longer be ignored. Because this is why:
https://vimeo.com/162214184
And that's after the caliper has "relaxed" a bit. The grinding was SEVERE, interestingly more so after /releasing/ the brakes. Just as interesting (to me, at least) is that the onset of this issue was pretty short. It went from "okay" to "DEATH TO ALL KITTENS" in a couple days.
Before starting I made sure to chuck the wheels & follow basic safety. Jack the car up, use a stand, don't leave it on the jack, keep kangaroos off at all times. You know, the basics.
After removing the wheel and carefully setting the nuts aside where they won't get Ralphie'd...
Then it went a little something like this:
Like a record, baby. But in a way that is NOT good.
I sprayed the caliper bolts and the heads of the two screws that hold the disc to the hub with Liquid Wrench and let it sit a while. That's the liquid visible on the concrete in later pics.
Removing the Caliper:
0) Under normal circumstances, a brother would be advised to pinch with vice grips the rubber brake hose that is behind the spring & shock in order to prevent fluid running all over the place. There are two of them, and it only takes a little bit of science-y eyeballing to figure out which is which. It quickly came to my attention that the hose is old and decrepit, pinching it might break it, and that was not an option. (Fast-forward to the end of this post if that bothers you as much as it does me) So....
1) Using an 11mm wrench, loosened the brake fluid line that enters the back of the calipier. Using speed & dexterity, as I pulled it out I quickly capped it with the bleeder valve dust cap. I lost a little fluid, but not much at all. Victory.
2) Using a 19mm socket (and preferably a nice, long ratchet or breaker bar, for leverage) the two bolts that hold the caliper to the hub were loosened. I switched over to a ratchet once I broke them loose.
Removing the caliper bolts with a 3/4" SAE nut. I cannot readily explain why I wasn't using a 19mm. Either way, worked fine. It took quite a bit of pressure to crack them loose with my short breaker bar. After that the bolts came out as easy as (having someone else bake me a) pie.
*NOTE*: Spanning the distance between the two bolts is a sort of washer/shield-esque piece of metal. There are tabs that are bent up flush against the sides of the nuts. These are presumably to prevent the nuts walking loose during operation. Some clever prising with a flat-tip screwdriver was all that was needed to shift these tabs out of the way so that the socket (or wrench) will fit.
Or in my case, they had been bent away and back before, and they just broke off. So, yay. Don't worry, I'll be back in here before too long.
But... how important are these little tabs?
3) The caliper came off pretty easily, just slid it off the disc.
4) Using a large cross/plus/phillips head screwdriver, I removed the two screws that hold the disc to the hub. To break them loose, I sharply rapped the handle of the screwdriver. They came loose easily enough, just a bit of wrist.
5) With a hammer I reached around and banged the back of the disc (at the "hole" left by the removed caliper) to loosen the hub. Again, it came off easily enough - just a few raps while turning it.
Now for cleaning & re-assembly.
ACDelco 18A83A Advantage Non-Coated Rear Disc Brake Rotor
Raybestos PGD21 Professional Grade Organic Disc Brake Pad Set
Dorman H100783 Rear Brake Hose
ACDelco 18K388X Professional Rear Disc Brake Caliper Hardware Kit
a pair of 10mm @1.0pitch x 20mm bolts to use as brake line plugs
a wire brush to take off crud
*NOTE*: These are not endorsements or even recommendations. They are just what I used. FWIW, all parts went right on no problem, nice fit.
Very much in the way of crud. Note also that the rubber dust covers are mangled. In fact, once the very stuck pads were pulled out, one could see that they were in fact doing more harm that good since a large section of it had split away and become lodged firmly between the piston and the pad. Given that I'll be back in here pretty soon, I though it best to just remove the rest of the cap to prevent it becoming wedged in again (and applying a camber to the pad).
Pad removal: they are held in with two pins. Using a small punch or even a medium-sized nail, tap them out with a hammer.
These calipers will have to be replaced, or the pistons therein will have to be rebuilt/repaired; and I will just as soon as I can afford the parts. This had to be done *now* because the caliper was not releasing fully and the grinding was Mordor-ific.
The brake fluid inlet was plugged with a screw to keep bits of crud from falling in during cleaning. Much brass brushing and degreaser later, the caliper was ready to be loaded with its bits.
The pistons were quite easily compressed using a c-clamp (making sure to release the bleeder valve first. Squirt squirt.)
Adhesive-backed anti-rattle/squeak shims are carefully stuck to the backside of the pads (on the face that contacts the piston).
The box came with a packet of silicon grease for lubricating slide contact areas, so, where the pad slides against the caliper, and between the caliper and the piston, and along the pins which hold the pads in place. I used an old toothbrush to apply the grease evenly & without overgooping.
The prepared pads are then placed inside the caliper.
I used a small spot of anti-seize goop on the screws that hold the disc to the hub. Nice and tight with the screws, but careful to not strip. Neighbors might see, that'd be no fun.
Since I was sure to compress both pistons fully, with the new pads in place the caliper easily slid over the disc.
Again with the anti-seize goop on the bolts that hold the caliper to the hub. I don't have a torque wrench (yet!), so I just made sure I turned them good and HARD - again, not so much that they will strip, break, or round the heads. I'd rather these not come loose.
Shiny.
Note anti-seize goop for lug nuts. Probably should have put that on after the wheel, but I was careful. No probs.
Test drive says, NO MORE GRINDING.
I'll be back in, though. Because:
Calipers rather urgently need reman or replace.
AND
HOW do I get the old rubber brake lines out? The ends that mate with the metal line are obvious, but I didn't see where to put a wrench on the ends that mate up to the body. And, is there a decent way to prevent fluid going everywhere? Or is it another quick & dexterous remove & plug?
