Mechanics

WHEEL VIBRATION

1994 Ford Laser

Shakes or Wobbles problem
1994 Ford Laser 6 cyl Front Wheel Drive Manual 180000 miles

Hi,

How are you?

I currently live in South Africa, So some of my terminology might be a bit different.

I have had this problem that when I Break going at Hi speeds 80-120KM the left wheel starts to vibrate. If I lift off the Break it stops.

I have had a few machanics look at it and they have no idea whats wrong with it.

I have had the Discs(Rotors) replaces twice, New Breaks, New Bearings and Hub, New Shocks, New Stabalizer but the problem still exists.

I hope you can help.

Thanks
Ryan
Avatar
Ikkichi
September 16, 2010.




Check and Replace the old caliper sleeve with a revised caliper sleeve. The new improved part is made of a harder material which is more resistant to wear spots and ridge formation.

BRAKES - ROUGHNESS CONCERN DURING BRAKE APPLICATION
TECHNICAL SERVICE BULLETIN

ISSUE
Early replacement of the brake components, rotors and pads due to brake roughness concern, is lowering customer's view of quality. The cause of brake roughness is due to small changes in braking torque when the brake is applied. The following are the major reasons for the brake torque variation: Runout of disc rotor
Rusted rotor surface
Warped rotor due to improper wheel lug nut tightening (torque too high or uneven)
Varied rotor thickness around the disk
Transferred patches of lining material on the rotor surface
Uneven tire wear and balance

Begin with step 1 and finish with step 6.
1. Check the Condition of Tires and Their Balance.
Sometimes the brake roughness concern is not brake roughness at all. In fact, some complaints are due to the out-of-round and out-of-balance tires or broken steel cord (for steel belted radial tires) in the tires. The effects of these problems show up at all conditions of driving, but may seem worse when braking. That fact can be used to correctly determine that the customer is not experiencing brake-caused roughness. If however, there is brake roughness in addition to tire problems, then both problems must be repaired. If the inspection shows that tires are contributing to roughness (vibration or roughness present in all driving conditions, not just braking) they should first be balanced and rotated using normal maintenance procedures then follow the steps below to correct the brake roughness.
2. Check the Wheel Lug Nut Tightening Torque.
Uneven and/or out of specification torque on the wheel lug nuts will cause the brake rotors to warp. Up to 0.005 inch rotor runout can occur due to improper lug nut tightening. The first thing to check for is the consistency of torque of the lug nuts on each wheel. If the torque readings are not within 20% of each other, that gives an indication of a cause of the concern of brake roughness. Improper lug nut tightening can have the following order of effect: a. Rotor runout b. Rotor thickness variation c. Brake torque variation d. Brake roughness
Ultimately, the rotor may be damaged and must be resurfaced. Follow the procedure in the Service Manual for resurfacing the rotors. Proper torque must be used when a resurfaced or new rotor is installed. Use of a torque wrench is again stressed, or as an alternative, the Rotunda " ACCUTORQ" 164-R0314 or equivalent must be used. When installing a new rotor, do not machine the rotor on a bench lathe. Any surface contamination can be removed with grease solvents or with very light hand sanding. Refer to #3, CHECK FOR RUST/ CONTAMINATION.
3. Check or Rust/Contamination on Mounting Surface
Surface rust or contaminations on the wheel-to-rotor and rotor-to-hub flange surfaces should be cleaned with very light hand sanding. Use garnet paper 100A or aluminum oxide 150J grit. DO NOT USE HARSH, ABRASIVE TOOLS. If the cleaning is not done, it will contribute to the runout of the rotor when assembled, which will cause brake roughness later on.
Any removal of rust on the rotor braking surfaces using harsh abrasive tools is not approved by Ford. The on-car turning procedure is the only sanctioned method at this time to deal with repairing rusty rotors. Since the thickness of the rotors are manufactured to less than 0.0004 inch tolerance, using hand held tools on the rotor surfaces can not guarantee maintaining the tolerance. Concerns will occur of brake roughness with rotor thickness variation of 0.0008 inch or less on certain very sensitive vehicles.

4. Check for Runout of the Front Rotor on the Car and Front Hub Mount 5. Check for Rear Brake Roughness
Except for the vehicles with separate drum in disc parking brake (e.G, Crown Victoria, Grand Marquis and Town Car) the rear brake can be actuated by actuating the parking brake. Attempt to slow down the vehicle from 48 km/h (30 mph) with the transmission in neutral using the parking brake. If roughness is present, then the rear brakes need to be serviced. If roughness is not present, then front brakes need servicing. To service the rear brakes follow the procedure, above for servicing the front brakes.
6. Check for Proper Caliper Operation
Inspect the calipers for leaks and brake fluid contamination. Any leaks from the wheel cylinders and seals must be repaired per the Service Manual. Also, inspect for glazing of the brake pads which may indicate a seized caliper piston, frequent severe or unintentional brake dragging by the customer.

BMRFIXIT
Sep 27, 2010.
Hi,

Ok I think it could very well be the caliper sleeve.

As most of the parts have been replaced with brand new parts IE: Rotors, Break, Hub, Bearings leaks have been checked

so alot of the actual things to be checked have been replaced with brand new parts. If I do rem correctly when the guy took the caliper piston had ceased and didnt move all that much at all he couldnt even pull it out.

I hope this makes sense?

Ill get the Caliper Pistons and sleeves replaced if I can do that.

As you mentioned.

Thanks
Ryan
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Tiny
Ikkichi
Sep 27, 2010.
After replacing the caliper sleeves recheck rotor run out and pads for uneven

BMRFIXIT
Sep 28, 2010.

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