I am beginning to see my lovely 745 as a time and money pit!

I just replaced the front rotors about two months ago with Zimmerman cross-drilled and already they are showing symptoms of warping - the pulsing in the brakes while coming to a stop. This is ridiculous; I simply don't have time to pull them apart again and try to tweak them. I could not find any marks on the Zimmerman rotors that ought to correspond to the marks (I also couldn't find them) on the hubs...is there a trick to this? The hubs were very clean, free of rust scaling, and with a very light layer of grease on them from the previous installation, apparently.

I am just discouraged - is it just something to accept about these cars' brakes that you can expect the rotors to warp this quickly? What can I do to prevent it from happening? Would Volvo OEM brake rotors be more reliable (durable)? AS always, thanks for the help, everyone!
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Darius in Albany NY '86 744 GLE (175K, given to my mother-in-law); '91 745 Turbo (167K-my 'Little Red Wagon')

I know 700 series cars have a history of rotor warping. We currently own four 700 series turbo cars, and have owned two others. I have not experienced a rotor warping problem. I buy new rotors, and have no brand allegience. I have not tried the Zimmerman cross drilled rotors, and I don't think they are worth the money. Check the strut rod bushings and the caliper guide pins.

Does your car have the single piston Jumbo calipers and rotors? If not, you might try upgrading to them. You can probably buy used calipers and holding brackets for less than $100.
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john

Got the Zimmermans from FCP Groton by mistake; they sent them instead of the regular ones and charged me only $40 each for them. Not a bad price. The car has the jumbo single-piston calipers and 11" vented front rotors.

Where is the strut rod bushing?
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Darius in Albany NY '86 744 GLE (175K, given to my mother-in-law); '91 745 Turbo (167K-my 'Little Red Wagon')

strut rod bushing-on the control arm, fixes the strut rod on the arm. the other end of the arm attaches to the body. 2 per side. use a BIG screwdriver or prybar to pry the outer washer away from the arm on the front. if it moves, replace the bushings. good luck, chuck.

The solution is to get good brakes and pads, and don't let ANY mechanic tell you what to put in your brick. The brick needs soft pads to insure the rotors don't warp, but many mechs put in hard pads that refuse to wear, heat up the disc, and cause warping.

For rotors on the front I have ATE Power Discs. They work very nice, have lateral grooves for heat and dust dissipation, and seem to wear well. On the rear I have, if I remember correctly, Brembos, but I can't be sure.

For the pads I like Roulunds, which are sold under the name "Dan-Block" in the US. The pads aren't too hard and aren't too soft, they have great stopping power, and they don't produce the god-awful mess that Volvo pads do (Volvo pads turned my rims red/black with a layer of cake).

When you replace the rotors make sure to replace the pads as well, and I would recommend doing everything once to get the car "working properly". Also remember, it is JUST as important to make sure your calipers are good and functioning properly when you replace everything. I didn't replace a caliper that was going when I last did my brakes, it started "hanging" and failing to release properly, and it warped the front right rotor (if it doesn't release properly it will sit against the rotor and heat it to warp).

So in short, get someone who knows what hes doing and supply him with the good parts you want on the car. You can find everything I've mentioned at http://www.importeccatalog.com, thats where I order from.

-rt

That makes sense since the quality of the pads is very high. I'm surprised that the Dan-Block/Roulunds pads I buy now aren't as messy as the Volvo pads, but maybe they changed the make-up or something over the years.

Regardless I STILL have cake crap from the Volvo pads on my rims, and nothing short of a 10 degree high pressure nozzle or acid bath is going to get it off.

-rt

I use Volvo OEM brake pads. I will check to see if one of the calipers is hanging. That could be the problem, and I can understand how that could quickly cause warping.
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Darius in Albany NY '86 744 GLE (175K, given to my mother-in-law); '91 745 Turbo (167K-my 'Little Red Wagon')

Yeah, it happened to me and I was so angry I could scream. My indy mech mentioned when he was replacing the rotors and pads that that caliper was "bad and not getting better" and needed to be replaced. I figured I'd wait until I could buy a new one cheap online and get it replaced at the next oil change. In the interim the caliper started seizing up (of course in the closed position) and slightly warped my brand new rotor.

The worst part was that the same thing happened to my dad (PO) on the same wheel years ago. So f#$%#$@% annoying, but whatcha gonna do.

Anyway, I've come to the conclusion the calipers are the real enemy on these cars. From stuck slide pins to bad units, they can cause major headaches in a blink if not properly monitored.

Good luck,
rt

I've replaced my rotors exactly once since I've owned it, and I'm happy to say I have never experienced signs or symptoms of rotor warp. Furthermore, supposedly there's no such thing as warping according to this site:

http://www.stoptech.com/whitepapers/warped_rotors_myth.htm

Parts I used when I replaced things: ATE Powerdisc slotted 11.25" rotors, Mintex girling brake pads

The brakes perform admirably. Perhaps I do get what people describe as pulsating. I'm not sure. Under normal driving circumstances, braking is very smooth, quiet, and there is no shuddering or vibration. Under very aggressive driving circumstances (very quick stops from >50MPH), I find that I feel a VERY slight rumbling during braking, but it disappears after the initial braking. I find this to be normal. Braking still works appropriately, and it's not by any means what I would call pulsating or shuddering.

On the other hand, prior to replacing those rotors, I made sure everything else was done properly. Suspension was all newly done with poly bushings. Ball joints and outer tie rods were brand new. Brake calipers were in good working order, no problems with the slide pins. Everything (wheels, suspension, etc.) was torqued almost exactly. So you may want to check all that.
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Kenric Tam
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'

Darius,
In addition to what has been said about checking other things, I will add that I never have a problem with warped rotors when I use Volvo pads (they are non metalic, I think). They wear out faster but it saves the rotors.

Hang in there,

Blessings!
Patrick

The rotors warp because of only two reasons:

1. improper torque at installation.
2. heat generated by frozen caliper slide pins or sticking pistons.

See the FAQ for tips to prevent this.

But Steve!!

The FAQ suggests that there is only one proper way to mount the rotor. Supposedly if it's not aligned properly it will wobble more than it would otherwise. Volvo rotors (again supposedly, I have never actually looked into this) have alignment marks. The FAQ suggests that rotors without alignment marks should be checked to see which mounting position results in the least runout.

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alex

'89 765T, 172,9xx mi

I thought my brake pulse when applying were rotors also. Front radius arm bushings.

how are the strut rod bushings? if they are loose or soft, this contributes to the rotor's warping.

a previous poster on the awd board also had problems with drilled zimmermans' warping. maybe it's not the car? good luck, chuck.