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Discussion Starter · #1 · (Edited)
HI TCCA !

I recently traded in my 1993 GL (RIP) for a 2000 SE 24V that hit 30,000 miles just today. It has front disks and rear drums. The boss told me earlier in the week that she notices a shake on the steering wheel when she brakes over 50 mph. Today I had the opportunity to test drive it on a suitable 4 lane road. There's no noticeable brake pedal pulsing or steering wheel shake anywhere up to ~50mph. However, between 50 and 60, with just medium braking pressure on the pedal, there is very noticeable steering wheel shaking and I can feel the front wheels shaking (but not the typical hard pulsating that you would expect when you would slam on anti-lock brakes). Over ~60mph, the symtoms seem to begin to disappear. It's as if it has warped rotors, or bad tie rod ends, but only in that 50-60 mph range.

I did a search here on TCCA and did find this one:
http://www.taurusclub.com/forum/82-maintenance-repair/159886-disable-abs-2000-sable-wagon.html
but it doesn't seem to point to any symptom that I could (safely) investigate in the driveway. They talk about disabling the anti-lock brake feature.

Any ideas, suggestions or comments will be greatly appreciated.

Regards,
Brcobrem

P.S. This new 24V v6 really gets up and goes! I'm very pleased with its performance. Like the adjustable brake/gas pedal feature too.
 

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Welcome aboard. The DOHC is a nice, durable motor indeed. Adjustable pedals are a great invention since the steering wheel doesn't telescope.

While you may think the rotors are warped, they actually have brake pad deposits embedded on them, causing the feeling like the may be warped.
Some excellent reading material here: StopTech : Balanced Brake Upgrades

First, I would suggest you go find a nice, open, somewhat vacant road you can stop quickly on (most importantly SAFELY), where you can have the vehicle reach speeds around 50-60 MPH, and not worry about causing an accident or something. Use the DOHC, get up to speed, and then mash the brake pedal to the floor like you would in a panic stop. Don't let up on it. Let the ABS pulsate. Just before you come to a full and complete halt (like 5mph), let up on the pedal and accelerate back up to whatever cruising speed and let the brakes cool for a few minutes.

Rinse and repeat this process 2 or 3 more times. The pulsation should go away.
 

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If it only occurs in that speed range, it may be a tire balance problem. Rotor runout is more temperature dependant rather than speed related.
 

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Wow, nice low mileage Taurus!

+1 to what Bull Geek said. It's free and only takes a couple minutes and just might solve the problem. If that doesn't do it I would suspect tire balance / alignment.
 

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Discussion Starter · #6 ·
Dear Forum Members,


Please accept my most humble apologies for not getting back to this post. Although I made sure to request notifications of replies, I have not had any come in. When this reply is saved, I will take a look at my mail service's junk folder. I suspect somehow your replies were trapped and I need to approve at least one reply so that doesn't happen going forward.


Thank you all for the excellent suggestions. I will let you know how it goes.


Regards,
Brcobrem
 

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Discussion Starter · #7 · (Edited)
Could someone please do a "test" reply. Perhaps I don't get notifications of my own replies to my own posts. I have now have "instant email notification" defaulted.
Thanks
Brcobrem

Followup: Thanks danhauser (see your thread below). It turns out that when I made my original post, I did not have "instant email notification" defaulted in my profile. So I made that change today. I also edited my original 4/2 post today and turned on "instant email notification" for this post. For whatever reason, it seems that I just am not getting "instant email notification" on this particular post and its threads. However, I did create a brand new test post in the Test forum, and "instant email notification" is working just fine there. So I expect that all new posts in the TCCA forums will work as expected. Thank you and Sheila again for your test threads.
 

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Could someone please do a "test" reply. Perhaps I don't get notifications of my own replies to my own posts. I have now have "instant email notification" defaulted.
Thanks
Brcobrem
So, howz it lookin?
-Dan
 

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Discussion Starter · #9 ·
Welcome aboard. The DOHC is a nice, durable motor indeed. Adjustable pedals are a great invention since the steering wheel doesn't telescope.

While you may think the rotors are warped, they actually have brake pad deposits embedded on them, causing the feeling like the may be warped.
Some excellent reading material here: StopTech : Balanced Brake Upgrades

First, I would suggest you go find a nice, open, somewhat vacant road you can stop quickly on (most importantly SAFELY), where you can have the vehicle reach speeds around 50-60 MPH, and not worry about causing an accident or something. Use the DOHC, get up to speed, and then mash the brake pedal to the floor like you would in a panic stop. Don't let up on it. Let the ABS pulsate. Just before you come to a full and complete halt (like 5mph), let up on the pedal and accelerate back up to whatever cruising speed and let the brakes cool for a few minutes.

Rinse and repeat this process 2 or 3 more times. The pulsation should go away.
Hi Bull Geek et al,

I know it's been a month of Sundays since you've replied with suggestions. Mid-May I did get the Taurus out for a run and applied Bull Geek's rotor cleaning procedure. It didn't work 100%, but it certainly did work at least 50%-75% on his particular vehicle. The pulsating on the steering wheel is still there a little bit between 50-60mph when breaking, but very, very much less pronounced now. The car is what I'll consider drivable now. I have a rotor resurfacing on the to-do list before Fall.

Thank you all again for your helpful comments and suggestions.

Regards,
Brcobrem
 

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Discussion Starter · #10 ·
Rome wasn’t built in a day and neither was this brake job project completed. The brake pulsating finally became very pronounced. So I bought a pair of rotors for about $40 each and a set of Wearever Silver semi-metallic pads at $19. Sounds easy enough, but Noooooooooooooo. I had to do the dumbest thing I have ever done with a toolbox. You will get a good laugh out this:

I unscrewed to break fluid reservoir lid and put a rag around the reservoir tank just in case the fluid would overflow when compressing the caliper pistons. I did the passenger side rotor and pads. Next on to the driver’s side.

I unbolted the caliper piston assembly and tied it up to the strut spring with a piece of coat hanger to get it out of the way. I then removed the caliper frame (ie. the part that’s bolted onto the axel assembly). I removed the old rotor and installed the new rotor (clean those surfaces with brake/carb cleaner to get the oil and fingerprints off). I reinstalled the caliper frame. I set the new pads in the caliper frame (they will stand up in there by themselves with no problem). I covered the piston surface with a ¼” thick strip of scrap wood to protect the piston ring surface (the part that contacts the pad) and used a very large pair of Channel Lock pliers (these open up to like 6”) to compress the piston. I removed the piston assembly from the strut and tried to put the top caliper bolt in. For whatever reason, I couldn’t get the top bolt to start threading in (always by hand first). So I lifted the piston assembly off the caliper frame to see if there was a piece of sand, or burr or whatever in the threaded hole. Still lying on my back, I bumped one of the pads in the frame and a pad fell out onto my chest. With the piston assembly still in my right hand, I picked it the pad with my left hand and reset it in the frame. This time when I lowered the piston assembly I had no problem getting the top bolt in. With the piston mostly compressed, I slide right over the pads. I put the bottom piston assembly bolt in and mounted the tire. Time for a test drive to “condition” the pads and rotor.

I started it up and pumped the breaks a couple times until I had pedal pressure again. As I backed out of the driveway I heard a sound like the pads were rubbing on the rotors. I thought, ok, these are semi-metallic pads on new rotors and they’re going to make a little noise until the surfaces get smoothed down a little. I hit the highway and did a breaking from 60 down to 5mph without engaging the antilock as much as possible. That noise because louder. This doesn’t seem right I’m thinking, but I sped up and did another “conditioning” stop. This time the noise coming from the driver’s wheel was much louder and now sounded like a continuous scrapping noise. I decided to forgo any more conditioning and head home. Think you know what’s happening yet?

By the time I got back you could hear me coming half way down the street. When I got and looked at the new rotor, it looked like I had put chunks of tool steel in there instead of pads. Don’t ask my how I did it, but when that pad fell out on my chest and I replaced it on it’s ledge, I PUT IT IN BACKWARDS ! CAN YOU SAY METAL TO METAL? That little act of stupidity cost me another $40 rotor and another $20 set of pads just so I could use 2 of the 4 pads. Like Homer says, D’OH!

Ok to lol at me today :lol2:
Brcobrem
 

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^+1
 

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Discussion Starter · #13 ·
Hi sheila,

Yes, the pulsating is gone completely. I have the smoothest beaking in town now :)

This time around I also paid attentention to an earlier recommendation and used a torque bar to put 80ft/lb on the lug nuts.

Here's something interesting too. Before buying new rotors, I took the old ones down to a local parts house and asked them to turn them for me. He measeure them and said there's not enought meat on them to do it. I said they're only ~38k miles and were never turned. He said the OEM parts are almost at minimum thickness when new, to keep the weight down.

So I compared the new ones to the old ones. Old ones were 1.06" thick. New ones where also 1.06". Go figure.

Where looking for the minimum number, our local county library provides an excellent on-line Auto Repair Reference Center (ARRC). It suggests that you shouldn't have them turned off the vehicle anyway:

Use On-Car Brake Lathe
201-00002 or equivalent
CAUTION: Do not use a bench lathe to machine the brake discs.
NOTE: Read the entire operating manual and view the video shipped with the lathe before installing, operating, or repairing the lathe.
NOTE: If the thickness of the brake disc is less than the minimum thickness to machine specification, install a new brake disc. This will make sure that the brake disc will be above minimum thickness after machining.
NOTE: Do not machine new brake discs.
NOTE: Lateral runout and disc thickness variation measurements are not required because correct adjustment of the on-vehicle brake lathe will make sure that these dimensions are within specifications.

Humm . . .
Brcobrem
 

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What's next? An advisory not to use tools to remove the calipers and rotors? I'd gladly sacrifice a few feet per gallon of fuel consumption for fatter rotors that will last a while. Rotors serve two purposes - contact area for braking capacity, but also as a heat sink for heat dispersal caused by braking friction. Less metal = higher heat absorption per cu. in. of rotor volume. To say the rotors are designed near the limits already seems counter-intuitive.

Sure hope that doesn't apply to my anteclintonian 1990 model.:D
 

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You could have checked for rotor runout by firmly setting the parking brake and blocking the rear wheels. Then jack up both front wheels and taking off the wheel/tires. Next start her up and put in gear with the engine at idle speed.

This will rotate the rotors fast enough to visually see runout, or you can hold any kind of non-sharp steel tool lightly touching the rotor and look for a gap to appear/disappear as the wheel rotates. Runout big enough to cause the issues you describe is visible to the naked eye. You don't need a dial indicator to detect it.

The old carpenter's saying, "Measure twice, cut once" applies to auto mechanics. Develop diagnostic skills instead of just throwing parts at a problem!
 

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Discussion Starter · #17 ·
Oops, sorry: I left out a chapter along the way: I believe it was this past November 2011, a neighbor offered to let me use his rotor runout gauge. It hand a magnetic “clamp” that stuck to the strut, then a dial indicator that you could position on the inner or outer rotor surface. Yes, I had to put the lug nuts back on, but I didn’t torgue to 80ft/lb, but rather just a little tight evenly. I turned the rotors by hand, and on either rotor, it didn’t show more than .001” runout. So to me at that time, there was nothing wrong with the rotors.

All I can think of now after the fact, is that when the lug nuts were torqued down, the rotors must have been going out more than that .001” . A parts guy thought that perhaps the axle bearings were wearing out, but I discounted that idea because of the low mileage (38k).

Anyway, 3 new rooters :)lol2:) and 6 pads :)lol2:) fixed the pulsating. That would be 2 new rooters and 4 pads for most people.
 
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