My 91 Aerostar does some serious shakin' and shudderin' when the brakes are applied. It is felt in the steering wheel as it shifts back and forth in my hands.
It seemed to improve when I put my winter studded tires on but returned after a few days. Thanks for any help.

 

How new are the brakes? Rotors been turned lately, or after a brake pad replacement?

Need some more info....

 

Brakes are new on the back and still good on the front. I checked them all when putting on the studded tires. When I replaced the brakes they were not to the point where they could damage the rotors.The problem never started after replacing the brakes but has progressively gotten worse over time, about one years time.

 

Did you do the brake replacement on the front? On my '93 there are slide clips with rubber bushing in the center, that hold the calipers in place, and also allow the calipers to slide. If these are failing, or are not functioning properly ( dirty, rusty etc.) this could be causing your problem.
I normally hit those clips with scotch-brite just to clean them up. Your rotors could also be warped. You might want to have them checked, just to be sure.

-reever

 

Mine did this too...but I know why mine happened.

This summer I was towing a Pop-up trailer (light enough not to have it's own braking system) down a steep grade and the wonderful driver in front of me decides to stand on his brakes for no apparent reason. After that panic stop, they shuddered afterwards.

I wore down the brakes in 1 spot - "Cupped" them. But, I did get stopped, which was the important thing. And for me, they were pretty worn anyway, so a pad replacement cured it for me.

Have you done a major panic stop lately? (since inspecting when you put on the studded snows?)

I'd say front brake pads are relatively cheap...try replacing those first.

 

Look at your rear drums- If you didn't set them right after installing them, you get a bad grip, which causes them to slip and cause shuddering. But since you feel the wheel shaking, you might want to take the thing to a mechanic, or a buddy with lots of auto knowledge, and check the rotors. If they're bent a bit, you'll feel the wheel move, and the shuddering is like going over multiple speed bumps.

 

your rotors are warped in the front. my experince it is just best to replace them and the calipers and hoses. by just cutting them when there warped that bad they usally dont last long till its shaking again. a bad caliper may be why there warped in the first place..

 

If indeed the rotors are warped, it was prolly caused by uneven pressure from the caliper(s). Those slide pins I mentioned previously are usually the culprit with A'stars.
t78 is correct about cutting extremely warped rotors. Might be better off replacing with new ones.

 

All,

I vote for warped rotors too. That's the only thing that's really irked me about my A*s, the front rotors seemed too small for the task. They would warp within 5-10K miles after replacement (and I overhaul the whole shebang when I do the rotors; pins, pads, shims, and all...). I know I'm hard on my vehicles, a lead right foot requires a lead left foot to stop when you're going that fast, but other vehicles I've owned (a '90 Ford police Taurus for example...) never warped rotors like my A*s have... I love 'em anyway!

DadVan

 

A police taurus? Sounds like bad news. Taurus and police don't mix. Only Crown Vic's and police do

 

Definitely rotors are warped. And do yourself a favor and buy a more expensive but reputable brand, offshore rotors will warp within weeks. Just put new and expensive rotors and pads on mine and the death shake is gone and braking is twice as good. Also Aerostar's actually have a left and right rotor and they don't mount the way you would think they should, make sure you know which is which side when you install them.
I wonder if we were to go with 15 or 16" rims, if mustang or crown vic rotors might work and provide way more stopping power????
Cheers
007BRONCO
Cheers.

 

I think we all agree that the Aerostars have insufficient brakes in the front. A minor improvement came in 1992 with the directionally vented rotors, as 007bronco referred to. The 1991 and earlier models got straight vaned rotors that were not directional. The directional rotors with the curved vanes do a better job of cooling. They seem to be working better for mine; a year after installation, and they're still running smooth. You need to install them so that the vents point backward at the top. Do not install them like scoops to pull air into the center of the rotor; the air flow is generated by centrifugal force, flowing from the center to the outside. Installing them backwards will cause stagnant air to form in the vents, so the cooling will be very poor. Just follow the instructions.

Someone also mentioned something about careful tightening of the lug nuts. If they aren't uniformly tightened to spec, they can warp the rotor as well. ALthough I think my (and most Aerostar) problems are heat related; if you don't use them hard, they seem to work smothly, but if you do run them hard, they overheat and warp. That's when you start feeling the shudders.

I wish there was a way to install bigger brakes on the Aerostar, but part of the caliper is integrated to the spindle. You would have to do some major metal reshaping of the spindle to remount the caliper in order to get a bigger rotor to fit there.

 

I priced out new rotors today at 44 dollars Canadian each. Its my wife with the heavy foot both on the brakes and the gas. I did recently get new tires put on and have had problems in the past with the lug nuts getting over tightened but knowing my wifes driving habits would tend to believe she has more to do with the problems with the rotors than the tireman at the tire store.Thanks again for all your input. I have never changed rotors but it doesn't seem to be too difficult looking in the manual. Any suggestions before I start. Should I change the brake pads too? They are about 1 year old, 10,000 miles or so, lots of wear left.

 

Make sure the pads aren't too bad, since warped rotors can hurt the pads. Make sure the pads aren't glossy or uneven. If they are glossy, just throw some sandpaper over them.

 

Printerguy: Be sure to have your new rotors mounted on a brake lathe and checked for "true". Can't tell you how many new ones I have had that are not perfect. Ounce of prevention before you install the new rotors only to take them off again and turn them.

Russ