Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

Seized . [Report: Don Willson] Pulsing brakes fixed. 1989 765T with ABS and 135,000 miles. I have not
seen this solution discussed though there has been plenty of comment on the problem and other remedies.
The symptoms were a pulsing of the brakes when light pressure was applied. I thought that it might be the
over tightened wheel bolts or a warped rotor. So I jacked up the front and started investigating. Yes the
wheel bolts were too tight but the rotor was true, they had been turned last June. What I found was a retainer
locating pin was frozen in place. In replacing pads about 4 times on my wife's 744 or my previous 745 I had
never realized that there might be other problems though if it had been a snake I'd have been bit.
One locating pin was free to move, I could push it in and the grease seal bellows would push it back out.
However the other was stuck. With about a half of an hour of twisting and prying I was able to remove the pin
without damaging the retainer though the pin was trash. At Volvo I found that you can only by a kit, 4 pins, 4
bellows, 4 caliper holding bolts and a tube of grease for $98. I objected but bought the kit.
Reassembly was simple though I did clean out the pin sockets and polish the inner diameters with
Scotchbrite on a stick on a hand drill, or use a cheap brass rifle cleaning brush. Reassembly was simple with
a liberal supply of grease and properly fitting the bellows. Then locating the brake pads and slipping the
caliper over the pads and fastening the caliper bolts to the locating pins. Since these pins are free to rotate a
thin 13mm open end wrench comes in handy to restrain the pin while tightening the caliper bolts.
Since I had the pins I decided to check the other side. I was not so fortunate, one pin was stuck so hard it
twisted off and I had to get a replacement retainer, $10.
My recommendation is that when replacing pads and or disks you check both retainers by pushing them to
the outside of the car. If they do not move freely remove the retainer (2 hex socket bolts) and get to a vise
where you can work the pins out. Replace the pins and bellows. Even if the retainer moves smoothly it might
not be a bad idea to remove the pins, careful not do damage the bellows, clean the socket of old grease and
any water and relube the pins. I suspect the grease is a silicone as it is water white (about like KY).
[Editor] See the notes under Caliper Corrosion and Brake Hose Deterioration for similar symptoms caused
by deteriorating rubber hoses.
Brake Calipers Rattle: Guide Pin Wear. [Tip from Dave Stevens] TSB 51907 dated Feb/94 covers '83-'91
700 series with Girling (Lucas) 2-piston front brake calipers. It simply mentions that excessive wear between
the caliper guide pins and their bores might, in some cases" cause a rattling sound and that a guide pin
replacement kit is available (P/N 271854-2) containing guide pins, bushings, dust seals and mounting bolts.
Obviously this was not a totally uncommon problem for Volvo to have even bothered writing up the TSB.
As you and the others notes, a much more likely cause for front brake rattling noise is a broken anti-rattle
spring on one of the brake pads. You can inspect these without removing the pads. If you're going to change
the pads you should always pop the dust covers, clean and lubricate the caliper guide pins using high temp
silicon grease. Use the same grease between the back of the pads, the stainless anti-rattle plates and the
piston faces to help minimize any tendency for your brakes to squeal. If you've got ABS, now is also the time
to clean up the tips of those sensors (check the 740 FAQ and archives for notes on this).
At every pad change you should check each guide pin in its bushing -mine wiggle a little and this is probably
normal, but slop is not. This gives you a chance to properly clean and lube the guide recess. Shoot with
spray brake cleaner and use a rifle cleaning brush to clean the inside of the bore. When removing a caliper,
hang it up with a length of coat hanger wire or a plastic tie to prevent damage to the brake lines.
Sticky Caliper: Internal Corrosion. [Inquiry] Despite replacing componens, I still have what seems to be a