I recently replaced my rotors and break pads on my 1993 240 and have some questions and some notes from the job.

questions:

1. One of the front calipers might still stick. Is this a huge problem. Will the pads just wear faster? How much faster? How much could it affect gas millage? Is it a safety issue.

2. The grommets on the calipers were badly damage, melted etc. How important is it to replace these things? The breaks seem to work fine without them. What function do the grommets serve?

Some of the rotors had deep groves and uneven pad wear from one side of the rotor to the other. Does this indicate a stuck caliper?




Notes from the job :

I had an corded electric impact wrench which can generate 350 ft lbs of torque purchased at lowes for $150. This made getting the lug nuts and stuck bolts on the front calipers off much easier. Some caliper bolts were not accessible with the impact in which case a BFH or extension tube for additional leverage on the ratchet was helpful.

It took 6 to 8 hours to do the job (first time doing breaks). Alot of time was used trying to get the stuck bolts of on one of the front calipers until I bought the wright sized fitting for the electric impact wrench. Getting some of the cotter pins out on the front breaks also wasted alot of time. The last two back wheels only took 1-2 hrs. second front wheel was also much faster.

I stripped one of the 10 mm bolts that hold the rotors on on the first wheel. These do not require much torque. This was done with a battery powered electric impact thinking a could just barley hit it with electric torque wrench and not strip it, not recommended ;-).

replacing all of the pad retention hardware was absolutely necessary

the front calipers were in much worse shape than the rear ones. It had been about 3.5 years since break work was done in the northeastern US and I think I would have just ordered replacement reloaded calipers for the front. Although this would have require bleeding air out of the lines after replacing the calipers. The car has 185K miles( a baby yet) I am not sure if the calipers were originals.

If I had to do the job again:

1. I would have inspected the brakes before ordering parts. Its easy to get the wheels off with the electric impact.

2. I would have replaced the front brake pad retain pins.


tools used:
bolts that hold the rotors on 10 mm
bolts on the back of the front calipers 15 mm
lug nuts 19 mm
rubber mallet
5 lb dead blow hammer
flat head screw driver
PB blaster solvent and lubricant to loosen bolts
needle nose pliers for cotter pin extraction
channel locks for compressing caliper pistons
bungee cord to suspend caliper from springs while changing the rotors
break cleaner to clean new rotor surfaces and old calipers.
anti seize compound for bolts
break grease for back of shims

a useful video:
DIY: Brake Job on Volvo 240 on Vimeo

 

Seems like you do have a stuck caliper. It will cause uneven wear, one side much worse than the other, and the pads wont last very long. It may affect mileage, and induce a pull to one side as far as safety.

What "grommets" are you referring to?

 

Yes this is a problem and a safety issue. It also is the cause of the uneven wear on the pads. It probably is the cause of melting of the grommets, etc. The grommets are there to keep dirt and water out of the caliper. Once broken, the dirt and water get in causing rust and sticking calipers.

When you have a stuck caliper, it rubs all of the time causing excess wear on the pad. Since it is dragging all the time, it overheats (melting grommets?) and the brake fades so you loose stopping capabilities on that wheel which will cause the car to pull to one side upon hard braking.

You have a choice of buying rebuilt calipers or rebuild it yourself. You can find kits online.

Brakes aren't something to skimp on as they are probably the most important item in you car relating to safety.

 

Yeah. Not being able to stop is regularly the cause of every accident.

"Boots" is the correct term I believe. That's what ACT1292 is talking about. I only posted this for other readers' to understand.

 

yes you are probably right Titan Joe, i.e. the piston dust boot ? I was going to suggest the plasticised rubber caliper pin/bolt tubes that later Volvos run, which i more thought of as being grommet-like...

 

7 year old post.

 

Just a few thoughts from me, correct me if i'm wrong !
1. You do not want a sticking caliper at all. There is no reason to let it go, if you have the caliper off anyway. Clean 'emup, smooth 'em up. Lightly brake grease up all pins and caliper slides and contact points (not bolt threads or maybe very lightly with copper grease)
2. Never use a rattle gun to start a bolt thread or final tighten. One has zero feel of the torque applied to tighten nor the freeness of the first 3 or 4 starter threads. One moment's thoughtlessness can lead to hours of pain.Stripped threads, broken bolts,rounded heads-.drilling, easy-outing,re-tapping threads, finding/sourcing or buying replacements....no need for it
3. Rotors need to be as smooth and be of minimum wear thickness usually 10.5mm solid and 18.5mm vented minimum but check factory spec..Most have the MIN. stamped on them. They are quite cheap and easy to replace so no need to skimp.
4. Bungee to hold up the caliper, good idea. I personally use cable ties, i always have loads of them...indispensible
5. Use brake grease not just on the shims/rear of pads but also on the caliper slides/pins and metal contact ares..just sparingly
6a. If there is even a possibility of overheating the rotors, keep an eye for deteriorated seals/boots(grommets). Personally i would replace the piston seal and outer boot etc while i'm there.
6b. Overheated rotor- I would renew the brake fluid, i would get a shop to do that. At least i would drain about 50-75ml of fluid at the offending bleed nipple whilst someone is constantly topping the reservoir. It is really only this short end of the fluid that the heat will affect to any great degree. Corrupted fluid should not migrate too far from this short distance if you catch the problem( overheated rotor ) quick enough. Most sources say one should replace fluid every 2 yrs., i'd say 5 but don't quote me, do what helps you to sleep at night and still keep food on the table

 

still a 7 year old post, but my two cents is for me, the days of rebuilding calipers and cutting rotors are gone. for the time and effort of removing/dissassembling/honing etc, the OP could have bought an after market replacement for about $50, dropped in fresh pads and fresh rotors and be worry free for the next few years. OEM parts availability and prices have dropped over the past 10-20 years while the quality has gone up. I find the install time savings worth more than savings on the cost of the parts.