When I was out recently in the 1500HL Dolomite that we have owned since new in 1977 and which has now over 318,000 miles on the clock as I was turning to park in a local supermarket car park there was a crack and the steering became less positive. On investigating I could see that the lower steering coupling was causing the problem. When I got the coupling out I discovered that one of the securing bolts had snapped. See photo lower steering coupling with broken fixing.
Over the years I have obviously changed a number of these couplings and looking at my records this particular coupling was fitted in November 2011 and the car has only covered about 37,000 miles since then. I do not remember if it was a new coupling or just a good previously used coupling. Prior to this I had fitted a group 1 escort type fitted to this car but as some club members had raised concerns about the escort coupling ability to clamp up tightly into the splines so I decided to change it. The steering rack itself has been fitted for a long time with one solid clamp on the nearside and a poly bush on the driver’s side. Prior to this I had found that some of the poly bushes on the market would allow the rack to move after a period of use but I think that my other three dolomites now have had super flex bushes fitted for a considerable time and they do not seem to suffer from the problem.
I had only relatively recently checked the car over to the best of my ability on my own prior to taking it in for its annual MoT and I sat and watch as the two mechanics thoroughly checked the steering and suspension and no problems were found.
I think I must have turned the rack to the full extent of its travel one way, in order to get into the parking spot and as I was still turning the steering wheel this put strain on the couplings bolts. I am just glad that the bolt snapped at this point in time and not when I was taking a corner at high speed. I think turning the steering wheel in both directions until the rack hits its stops with some force will be a check that I will introduce as part of my own pre MoT checks.
Having now looked at the coupling more critically I do question the small diameter size of the bolts used for such a safety critical item. I do accept that is the first time I have come across this failure as the normal failure mode is for play to develop in the bushes. Has anyone else had a similar failure?
I did wonder if the sub frame was moving about and had caused the problem but my initial inspection has indicated that this is not the case or is it just the state of the roads which has put the coupling under more stress.