Front end clunk - now pulling left

cycleguy55 · #1 (**permalink**) 09-11-2015, 10:35 AM

I have an original Mustang II front end in my car. The UCA and strut rod bushings were replaced about a year ago with Energy Suspension black (graphite impregnated) urethane bushings and I'm running QA1 coilovers. I had a wheel alignment about 2 months ago and have logged about 500 miles since then.

A couple of days ago I was backing out of my driveway and was rolling a bit quicker than usual when I hit the brakes firmly with the wheels turned to the left. There was a somewhat disconcerting clunk from the right / passenger front suspension and, since then, there is a noticeable increase in negative camber on the right / passenger front wheel and the car pulls to the left.

It seems the most logical explanation is that the UCA mount must have moved - probably inward at the front of the UCA. It's booked into the same alignment shop that last worked on it, but I'd appreciate some expert opinions before heading there next week.

Thoughts?

Chuckr · #2 (**permalink**) 09-11-2015, 11:58 AM

A few things pop to mind. 1) the caliper isn't releasing the pads or the pads are hanging up and slightly dragging. 2) Loose calipers. 3)You may have a collapsed flexible brake line. 4) wheel bearing drag. 5) improper tire inflation...... and on and on.

Were you cutting the wheels at the time?

427sharpe · #3 (**permalink**) 09-11-2015, 12:29 PM

Think you are correct about upper control arm movement--the Mii's were known for the UCA nuts losing their grip. The serrations on the flange of the nut wear out. Should be easy to check as it probably scraped the mount pretty bad. If not, just compare to other side; they should be about the same as far as location from alignment. Brakes would usually only be a problem when braking unless a caliper locked up by circumstance.

cycleguy55 · #4 (**permalink**) 09-11-2015, 01:59 PM

Quote:

Originally Posted by 427sharpe

Think you are correct about upper control arm movement--the Mii's were known for the UCA nuts losing their grip. The serrations on the flange of the nut wear out. Should be easy to check as it probably scraped the mount pretty bad. If not, just compare to other side; they should be about the same as far as location from alignment. Brakes would usually only be a problem when braking unless a caliper locked up by circumstance.

If the serrations wear out on the nuts, would replacement nuts with fresh serrations aid in preventing a recurrence? I see Speedway has a kit with 4 T-headed bolts and nuts - is this what I'd need? (Mustang II Upper Control Arm Bolts) It looks like the threads are standard 1/2" x 13 TPI, so I'll check into picking up some nuts. I would also expect a shop specializing in frame and wheel alignment would stock such nuts.

I note the UCA cross shafts have holes, not slots - those are in the spring hats / mounts, so any movement would have to be the UCA cross shaft moving relative to the spring hat. That leads me to believe it may have not been properly tightened with it was last in for the wheel alignment. Make sense?

I drove it about 30 miles after the 'clunk' and detected no signs of a brake dragging. Regardless, the clunk was right front and it would need to be a left front brake to make it pull left.

427sharpe · #5 (**permalink**) 09-11-2015, 07:29 PM

Those are the nuts, and a good alignment shop will have them IF they still do a lot of Mii front ends; although a .500x13 nut would have many uses, I am sure.
Your logic on the lack of proper torque by the shop makes sense. It is also possible that if the right suspension moved enough it could 'push' the car left just as if you were steering the car to the left. That much movement should be visible to the eye I would imagine (but I don't know how severe the pull/push is, either!). Either way, I hope it's all taken care of without drama and you get back to happy motoring!
Robert

keezling · #6 (**permalink**) 09-12-2015, 10:21 AM

I don't mean to stick a broom handle in your spokes but I would be suspect of the alignment shop having left one of the lock down nuts loose enough to move. A problem in the front end after someone worked on it really throws up a red flag to me...

keezling · #7 (**permalink**) 09-12-2015, 10:24 AM

oops, should have read all of the last post. My bad

cycleguy55 · #8 (**permalink**) 09-12-2015, 02:06 PM

Quote:

Originally Posted by 427sharpe

Those are the nuts, and a good alignment shop will have them IF they still do a lot of Mii front ends; although a .500x13 nut would have many uses, I am sure.
Your logic on the lack of proper torque by the shop makes sense. It is also possible that if the right suspension moved enough it could 'push' the car left just as if you were steering the car to the left. That much movement should be visible to the eye I would imagine (but I don't know how severe the pull/push is, either!). Either way, I hope it's all taken care of without drama and you get back to happy motoring!
Robert

Like I wrote earlier, I drove the car about 30 miles and, during that time, it took a steady tug on the steering wheel to keep it from going left. It also turned left a lot easier than it turned right.

Yes, the shift is visible to the naked eye. I just checked the camber on the RF wheel, and it looks like it's about -2°, when it was -0.1° per the last alignment report.

cycleguy55 · #9 (**permalink**) 09-12-2015, 02:10 PM

Quote:

Originally Posted by keezling

I don't mean to stick a broom handle in your spokes but I would be suspect of the alignment shop having left one of the lock down nuts loose enough to move. A problem in the front end after someone worked on it really throws up a red flag to me...

I'm taking it back to the same shop for a couple of reasons: 1) it they missed something or somehow screwed up, they need to fix it; and 2) they have a very good reputation around town. I've dealt with them before, and there has never been an issue with their work.

After 22+ years in the IT services business I understand that everyone can make a mistake, but often the real test is how they deal with it.

427sharpe · #10 (**permalink**) 09-13-2015, 08:01 AM

Quote:

Originally Posted by cycleguy55

... I understand that everyone can make a mistake, but often the real test is how they deal with it.

What a refreshing attitude! Good luck!
Robert

cycleguy55 · #11 (**permalink**) 09-18-2015, 02:06 PM

In and out of the shop on Wednesday, and all is good now. Turns out my assessment was correct, and it seems the UCA cross shaft shifted relative to the spring hat. The front bolt on holding the cross shaft to the top hat must not have been properly tightened during the wheel alignment in July. I don't know whether they put a piece of pipe on the wrench this time, but I tried tightening it further when I got it home and it didn't budge.

BTW, it appears there are serrations are on the bottom of the cross shaft. They're supposed to 'bite' into the mounting surface once the bolt is tightened sufficiently, thereby preventing movement. That's the theory anyway. I guess if the serrations don't hold you replace the cross shaft.