I have a 1954 XK120 OTS that I have owned for 51 years. I had it restored in 2012 and put in a used steering box since the old one had some bearings missing. The car ran fine until 2016 when it experienced a severe vibration at 35-40 mph. I slowed down and it stopped and I was able to continue driving. I replaced the steering idler. About a year later the same thing happened. My mechanic (different one) tightened the steering box and said that was the problem. A year later the same vibration happened and I slowed down and it stopped. I tighened all the suspension components. It happened again. I had new shock installed and the suspension again inspected. It happened again. This time (2020) the mechanic did a front end alignment, rotated tires rear to front, balanced wheels, and tightened the suspension some more. The ball joints seem tight when the tires are unloaded and there is no play in the bearings. The steering seems tight with little play. Well it is happening again. Twice in one day. The entire front end shakes violently as if the suspension will fail. It is so violent the horn relay goes off. The whole time I get a slight vibration from 58-62 mph and have never been able to get rid of it. I am at wits end. May I get some suggestions. My inclination is to investigate the steering box itself. All these incidents have happen between 35-50 mph on smooth and bumpy roads. Thoughts?????? I am very concerned if this happens on an interstate highway at 70 mph and I have to suddenly slow down. I drive the car about 4500 miles a year. Thank you for your thoughts.

 

Rick the common fix--even when the cars were new and that happened was to increase the toe-in! There were bulletins that covered that/. Also what type and size of tires are you using and is your car steel or wire wheeled?

 

Coventry Foundation, Thanks for response. My tires are185HR16 93H Vredestein. I replaced them all four years ago thinking maybe the vibration betwen 58-62 mph was a balance and tire problem. Not. I have wire wheels. I have rotated the fronts to the rear to see if one of the wheels is bad and it had not effect. Still infrequent severve front end vibration. I will try and increase the toe in and see it that helps. I will let the thread know how it works out.

 

How are the rubber bushings looking? Shock bushings? Something in restoration that was not done?

 

Jagfixer, Myself and the import shop I use have checked all the bushings, ball joints, wheel bearing and steering wheel play. They all appear in good shape. None of the bushings are damaged or look hard. They were all replaced in 2011 by the restoration shop or so they said which is why we have studied them again several times. I am going to toe in the wheels a bit today and while I am at it I am going to check the motor mounts.

 

Jagfixer, The import shop replaced the front shocks in October 2019. So we have crossed that item off the list. Running out of suggestions.

 

Coventry Foundation, I toed in the car yesterday and it did not correct the problem. Still a severe vibration like the front end is coming off on a semi bumpy road around 40-50mph. Slowed down 5-10 mph it stops and I can continue driving. I had the steering idler repalce the first time this occurred in 2016. There was no issue of 18 months and then this issue has come back. Does anyone think maybe the steering idler failed prematurely? It was a rebuilt unit I think. The shop that did it did not say exactly what condition the idler was in, new, rebuilt or used. Would the steering idler cause this effect? Rick W

 

Factory settings, Castor 3 deg negative, 5 deg prior to chassis 660126 rhd, 670439 lhd
. Camber 1 3/4 deg to 2 deg positive
. Swivel pin inclination 5 deg
. Wheel alignment 1/8" to 3/16" toe-in
Hope this helps.

 

Factory settings, Castor 3 deg negative, 5 deg prior to chassis 660126 rhd, 670439 lhd
. Camber 1 3/4 deg to 2 deg positive
. Swivel pin inclination 5 deg
. Wheel alignment 1/8" to 3/16" toe-in
Hope this helps.

 

 

Also - it was recommended to me, and it has worked for over a year now, to make this change (note especially that ball joints go in DRY - *NO* grease) and to tighten up the ball joints to only .002-.003" float. As a result, ball joints will likely be a routine maintenance item.

 

360gtracer, Thank you for the service bulletin. Since my car was built in December 1953, I believe the changes to the suspension were incorporated into the car. I will check to see if the cap or plug on the bottome. I am pretty sure there is no grease fitting. I will check. Thanks for response. RickW

 

Jag fixer, My chassis is 674554 so it is a bit different. I do have an orginal manual I bought in 1970 from Somerville, MA Jaguar. It has the specs. Thanks.. RickW

 

Hello, if you are still fighting this problem, I would recommend having your wheels checked by an expert. I know you said you had them balanced, but did anyone tune the spokes? Seems like that shouldn't be a huge problem, but I had some incredible wheel shake on my 140 OTS and it was due to the spokes being untuned and actually breaking. Just a thought as you seem to have done everything else under the sun to fix the problem. I'm still running with at least 40-year-old front end parts and have no problems up to 85 mph, but did experience low speed massive wheel shake in the past due to bad wheels. Good luck!

 

Since you are using Radial tires I would adjust the Camber to 0-2 degrees negative!
It will handle better that way, no idea if this will resolve the vibrations, but you could give it a try

 

Thanks to Walt at Vintage Jag Works in Idaho in diagnosing my death wobble problem with my XK120. The castor was off. The top ball joint needs to be 1/2 to 3/4 inch toward the rear of the car than the bottom ball joint. Did it and solved the problem.