NEVER pump the brakes with the calibers off the rotors (or with no pads), or the pistons will likely blow their seals as they over extend.

 

that last picture, those are the shims, and yeah, they need to be in there with your new pads.

 

Yeah, I suspected I hadn't quite suffered enough. Gotta get back out there and get this all done before the car is buried in snow. Please send more tips, cautions, &c. as you think of them.

UPDATE: With shims in, rotor makes a "shhhh" type scraping sound moving past pads, please let me know if this is OK.

 

Did the shims come with the new pads? Some pads have shims, some don't. The shims should be attached to the back of the pads securely with the clips. I use a rubberized "anti squeal" on the back of the shims where they contact the calipers.
Everything looks good but you need to bleed the system now and renew the fluid as you are doing it.

 

Hey Lev. Yes they came with the pads. They seemed to adhere pretty securely to the pads by those tabs.

I look forward to the bleed-and-replace (would be grateful for a step-by-step), gonna jump out there now and finish the left front brake before the car is buried in snow...

 

Well, I am fearing the worst. When compressing the pistons on the left front brake I noticed that the bottom bleeder valve was bleeding much more than the top valve. When I was done and took a look at the pistons I saw something I don’t remember ever seeing on the other side, namely the gap indicated in yellow. (The top rubber thingy seemed weirdly smushed and when I tried to straighten it, it popped out and looked the same way as the bottom one as pictured.)

Is this the seal rupture you were warning against, pierce? Is this the end of this caliper (and by extension the other one)?

 

No, these are only dust shields. You should be able to push them back in place by pushing the piston out CAREFULLY not too far and putting the rubber edge in the groove. Looks like the pistons got pushed in too far...

 

when brakes have been neglected a long time, the piston walls tend to corrode outside the region the piston normally travels in, and when you push the piston too far in or out, the corrosion will damage the piston seal, then they will start leaking brake fluid.

 

Hey, relieved to hear it... but how to push piston back out? Is it a matter of gently pumping the pedal with the bleeder screws re-tightened (and if so, do I close both sets of bleeder screws or just the side where I need to push pistons out)?... Also, when I straightened out the top dust shield it looked as though they were both equally far in... I was admittedly having a hard time getting the caliper to close over those shims and must have overdone it...
So might that damage already have occurred here?...

 

Close all bleed valves and apply the brakes gently a little at the time to push out the pistons to be able to put the rubber shields back on.
Don't worry about possibly scarred pistons, it may happen but rarely does, (theory vs practice). No point sweating it now.

 

Hey lev, will do, thanks for tip (and perspective). More soon.

NOR'EASTER UPDATE: Gotta dig out first. (Covered the car though.)

 

Finally

dug

out.

(I’ll send a pic in the AM.)

Long story short, dust shields are back on, calipers closed nicely over shims.

I’d be very grateful to get a step-by-step for replacing brake fluid (hardly any in reservoir by this point), including a recommendation on what type I should use.

Feels good to be close to the end, for the winter anyway (don’t think I’ll be getting to that center bearing till spring)...

Thanks very much again for everything...

 

Good job!

This is a good bleeding write up:All you need is a turkey baster, a piece of 1/4" I. D. clear vinyl tubing and a coke bottle. Have 2-3 pints of the proper brake fluid on hand. If you are changing a part and air is already in system, then the order is important. If you are doing a flush/bleed then the order is not important. Use a turkey baster to suck out most of the old fluid from the master cylinder reservoir. Refill with fresh fluid. Leave the engine off. Go to whichever caliper is first in the bleed sequence and loosen the bleeder 1/8 turn. Attach the clear tubing and place end in coke bottle. Add just enough clean brake fluid to coke bottle so that tube is below the fluid level. Get in car and pump pedal slowly about 1-1/2 inches 10 times. Don't exceed this extension or you will press the master cylinder seals into corroded areas within the master cylinder and ruin them. Get out and check/top up fluid. See if the fluid in tube is clear, if so close bleeder and remove tube. If not, pump five more times. Go to next caliper and repeat until all have been done. The bleeder screw opening should be just enough to allow fluid to pass out. This can be determined by feeling resistance as you push pedal. If the pedal goes to floor w/o resistance then you should turn in bleeder screw 1/16 turn. The idea is to do have resistance to the master cylinder suction pulling fluid back in through tube. This way the fluid will be pulled from reservoir on upstroke of pedal and you will not need to do the pump x times, hold, open screw, close screw, pump x times thing. I have done this for 25 years and never had a problem and never had arguments with girlfriends, co-workers, family members as I didn't need their assistance. IF you have a bunch of air in system then you will have to do the pump-open-close pump routine. For ABS-equipped cars, see the notes on Brake Fluid Bleeding/Flushing Procedures for Cars with ABS. If you have lots of air in the lines and master cylinder, tap them as you bleed to loosen adhered air bubbles.

Brake Bleeding Sequences.
Bleed the brake lines in this order:

• Cars without ABS and 1988 or later models with ABS:
  • LR, RR, RF, LF.
• Cars with ABS up to and including 1987:
  • use the reverse sequence: LF, RF, LR, RR.
• On Volvo models with 2 bleeder screws (upper and lower) on the front calipers: bleed the upper nipple
• On Volvo models with 3 bleeder screws on the front calipers: LR, LF top, RR, RF top, LF two bottom bleeders, RF two bottom bleeders (per Bentley)
• Highly recommended: use a pressure bleeder as noted below at Brake Pressure Bleeder

[Editor's Note: when bleeding, use the uppermost nipple to expel any air. When flushing fluid, use the lower nipple, then close and check the upper nipple for any

 

Hey lev, this looks great, thank you.

Ran a short test of the brakes round the driveway loop (10MPH max). Saw this wear pattern on both rotors.





Reminded me of the pic I took earlier of the old rotors, on which pierce commented, saying it looked like the pad wasn’t making full contact.



Wondering if I need new calipers.

UPDATE: Sorry if I'm freaking out here about the rotor wear.

Hey lev, just notice this last bit got clipped from your copy-and-paste? Could you supply?

 

Hm, that doesn't look good! How did the new pads fit on the rotor? They should be making full contact. How did the pads fit inside the caliper? If they fit snugly in the caliper, then the rotors are wrong, too big... There really shouldn't be that much space above and below the pad. I see the old set of rotor/pad and that is the same pattern as the new.

On the other hand, if the pads make full contact with the rotor there now, even though there is space on the rotor surface where the pads don't make contact, it'd be OK, though not optimal... Logically, the rotor should be smaller or the pad bigger.

 

Hey lev. After I finally developed the right touch for compressing the pistons (and after putting dust shields back in place), both front calipers closed over their pads & shims quite nicely/snugly. (There was a tiny bit of pressure required on both sides to line up the holes for the bottom screw that secures the caliper closed, but nothing crazy.)

RE: pads to rotors, as I recall they were making contact fully/squarely, but I will have to get back under there and check this evening.

RE: rotor size, IPD offered up that rotor (Bosch QuietCast) as a fit and I chose it because it's what was on there before; they offer other rotors as fits too but they are similarly sized (10.25 inches; one rotor they offered was actually 11.25 inches)...

UPDATE: Could you explain this bit of the bleed/flush write-up?

 

when bleeding, use the uppermost nipple to expel any air. When flushing fluid, use the lower nipple, then close and check the upper nipple for any trapped air.

 

I don't use that method as I prefer a helper pushing on the pedal as I work the bleeder which this is supposed to eliminate. I assume this is when you use a bleeder device.

 

Hey guys. Phone dead, so no pics, Merry Christmas. Hope you guys are well.
So I did check the fit of the pads. Pads seemed a good close fit, and yet they were showing a "slender band" of wear matching the pattern of wear on the rotors I've already illustrated. But while closing up the right hand front caliper I caught a glint of what appeared to a drop of brake fluid hanging at each bleeder screw tip. I found that each screw tightened about a 1/4 turn (!); I did think they were tight on there before but now they're all-the-way tight. I checked and found the front left screws also tightened a 1/4 turn further (!!). Subsequent braking tests seemed to produce a "broader band" of wear on the rotors, seemingly indicating better pad contact. Was this all it was, just making sure not the tiniest bit of pressure escapes the braking system (as was the case with the fuel system)? Where else should I be checking for pressure failures? (Or it is more likely that at bottom I am dealing with less-than-fully-responsive calipers here?)
Thanks once again.

 

Leakage from anywhere is not good, but as you tightened them and they are OK, as long as you are getting good, firm pedal pressure you should be fine, once there are no leaks obviously.

As far as the pad footprint, leave it alone as long as all other functionalities are OK.