shimmy at 55 mph

I have a '96 Cherokee w/ 93,000 miles (4x4, auto, I6) and am experiencing two problems.

1.) Brake shudder @ 55 MPH when braking from highway speeds (nothing higher but shaking at 55MPH harshly then it stops just under 50MPH) - I'm thinking my rotors are done for (they were cheapy's from Murray's which I needed to replace in a hurry). What do you think? Even when I'm coming to a stop I can feel in the pedal and Jeep a type of binding in the braking at an interval of the tire turning so the rotor (mainly passenger front is bad).

2.) vibration @ 55MPH when crusing - It's causing the steering wheel to go side to side. I've grabbed onto all steering components and tugged on them but nothing seems loose. I just got the wheels balanced today and there is no difference. Pleae advise.

Thanks.

I have a '96 Cherokee w/ 93,000 miles (4x4, auto, I6) and am experiencing two problems.

1.) Brake shudder @ 55 MPH when braking from highway speeds (nothing higher but shaking at 55MPH harshly then it stops just under 50MPH) - I'm thinking my rotors are done for (they were cheapy's from Murray's which I needed to replace in a hurry). What do you think? Even when I'm coming to a stop I can feel in the pedal and Jeep a type of binding in the braking at an interval of the tire turning so the rotor (mainly passenger front is bad).

2.) vibration @ 55MPH when crusing - It's causing the steering wheel to go side to side. I've grabbed onto all steering components and tugged on them but nothing seems loose. I just got the wheels balanced today and there is no difference. Pleae advise.

Thanks.
AHH its the good ole death wobble, i would replace the rotors you may even be able to get em free from jeep because there was a recall on those :runaround: you can go to the jeep website and put in your vin# it will tell you if it has been done on your jeep, there are so many different causes of the Shimmy i have had the same problem and just decided to live with it ive replaced the entire front end:banghead: stilll have the shimmy try balance rotate front end aligin etc... Do you have a lift on your Rig? if so the vibe may be from the drive line out of sink you can get transfer case drop spacers to correct that problem OR if you dont have a lift then it could be a sign of your U-Joints going bad. Either way its a long slow hit or miss problem make sure everything is tight on the front end and just start at one thing at a time, tie rod's u joints ETC...:rofl:

I just got done replacing both the U-joints and upper and lower ball joints on each side.

I didn't know about the recall issue. I'm going to have to investigate that. Yeah, what is frustrating is that those crappy Murray's ones are < 1 year old...oh well.

Anymore suggestions on what to look for to replace is also appreciated.

The most common problems for death wobble are the steering stabilizer worn out, tires out of balance, wheels not totally round (like from hitting pot hole or speed bump hard), loose or worn out ball joints, tie rod ends, damaged steering components like bent tie rod. Since you already had the tires balanced i'm assuming that you had the front end aligned at the same time if not give that a try as well. After that replace the steering stabilizer as that is often the most common problem for death wobble. Having a lift on your jeep will not cause death wobble to occur you would feel a vibration in the floor and no movement of the steering wheel. Since you said it also does it when braking I'd also replace the front rotor's and pads. If after replacing the brake parts and the steering stabilizer it still does it at cruise and braking then it's possible it might be in the steering box but unlikely, or possibly the brake system causing the front brakes not to grab at the same time.

also check your wheel bearings for adjustment,if they are loose will do the same as bad tie rods or ball joints.

You don't have Death Wobble.

I have a 55 mph issue like yours...but only when the gas tank is down to 1/4...

It is an alignment issue, "caster", which decreases when the gas tank empties and weight transfers foward.

DW is a severe shake, which I have also felt, caused by loose parts and or warped disc brake rotors.

I think one of the other guys mentioned "wheels not being totally round". Before you go tearing into it, try the easy stuff first.

Believe it or not, tires and rims can be a bit off as far as "roundness" goes. Find a *good* tire shop, one that is familiar with "match mounting" tires. Shops that handle high performance tires and wheels would be a place to start. Match mounting tires is a procedure used to compensate for high and low spots on rims/tires. The wheel/tire assembly is placed on a Hunter balancing machine that has the capability to determine the highest spot on the tire and the lowest spot on the rim. The tech uses chalk to mark the high and low spots then unmounts the tire. When remounting, the chalk marks are lined up so that the highest area of the tire is compensated by being mounted on the lowest spot on the rim. This will usually take care of your problem if it is a tire/rim mismatch.

I have a bum rim on my 2000 Sport; when it is mounted up front, I will feel exactly what you are experiencing...but when the tires are rotated and the bogus rim is on the back, the steering returns to normal....that was before getting the tire match mounted....after having it done the shudder/shimmy quit. I just got new tires on my ride and the shop did not have the equipment to match mount (Discount Tires....whaddaya expect?)...so I'm back with the 55mph shudders. I'll go back to my normal mechanic and have them do some magic again.

BTW, this is the procedure the factory uses when the vehicle was new...according to my D/C factory service manual.

Hope this helps and good luck.....

Mike
00XJ