Topic

In this thread ( LINK ) Paul (PQD44) showed us that the outer ball joint of the MGF rear track control arm was exactly the same as the Rover 200 track rod end.



In the thread, there then follows a long discussion about the inner joint and whether it is replaceable.

MGF arm




According to collective wisdom there is no availability for this part and the recommended solution is to replace the whole arm.
Now this inner bush/joint is a frequent failure on MOTs. I have replaced both arms previously to pass an MOT, and also subsequently took off the rubber boots and filled the joint with silicone, before re-assembling. This got me through another MOT.

Allan(Diesel Destroyer) went so far as to show how to remove the old ball joint and ordered some polybushes that seemed to be the ones needed.

He subsequently found out that the bushes he received were for the inner joint of the lower suspension arm, not the rear track control arm.


I noticed that the joint in question looks very much like the outer ball joint on an MGTF rear track control arm, for which there is a POLYBUSH equivalent



MGTF arm



I was prepared to gamble that the two parts were the same and ordered a set of polybush replacements from Rimmer Bros for the outer TF joint. My thinking being that if MGR wanted an outer balljoint for the TF that was very similar to the MGF inner balljoint, they would very probably just have used the same part!

So, armed with these polybushes and a spare track control arm, I dismantled the inner joint much as Allan did and guess what?

The polybush is a perfect fit.

I did come upon one little problem in that the SS inner sleeve is a couple of mm too long to fit into the F subframe. This I solved with an angle grinder.Taking thesleeve down to the same length as the original.

So, the polybushed arms are now in place and testing is taking place. I was very careful to ensure that the arms stayed the same length as the originals, but a 4 wheel alignment is advisable.

So far the car handles perfectly well, and the rear track control arms are noticeably firmer.

First thing is to jack up the rear of the car, chock the front wheels and add axle stands to make a stable safe working area.

Next, wire brush the centre adjuster rod of the track control arm (TCA) and the 19mm bolt that holds the arm to the subframe. I use a good penetrant spray to ease the next part.

It is important to release both locking nuts before removing the arm. This becomes much more difficult if you remove the TCA first.
Once the locking nuts are free, ( note that the inner is a left hand thread), hand tighten them back up and mark the adjuster so that you can re-assemble the TCA to the same length.

Remove the 19mm bolt completely from the inner. Take off the 17mm nut from the outer and split the balljoint with your tool of choice. I use one of these as you have a fighting chance of being able to reuse the balljoint.ie the rubber boot stays in one piece!






You can now remove the entire TCA.

Separate the inner section from the rest of the arm.



Note the thread direction.

Now remove the rubber boots from both ends of the joint.





You will now be able to see the ball inside the joint. If you clean up and examine it, you'll be able to see that one side is actually a pressed in steel collar.

You need to knock this collar in towards the ball, using a hammer and chisel or old screwdriver. Keep working around the collar until it deforms enough to get a screwdriver under it. Then lever it out.

The ball runs in a plastic cage type race. To remove the ball section you need to get rid of the plastic race.

You can use brute force and a big hammer but the easiest method I found was to burn the plastic out with a blow torch. BE VERY CAREFUL, as the burning melted plastic will drip out until the HOT metal ball just drops out. Don't set fire to your T shirt or anything silly like that!



Remove any remnants of plastic from the interior.

At this point it is good practice to smooth off the faces of the aperture to reduce sharp edges that would cut into the replacement bush. I then coated the finished piece in a fetching sky blue.

Then using a good lubricant,(ooh err) I pushed the bush into place. I used a vice to get the bush fully home.

This is what I now had.



Now I compared the inner ss sleeve with the original and found it be a few mm longer.





I adjusted the length with a grinder until it matched the original.

I pushed the inner sleeve into the bush and I was ready to re-assemble the track control arm. The inner bush was a nice tight fit into the subframe and I refitted and slightly tightened the 19mm bolt. I reconnected the ball joint and tightened it up to the specified torque(30n). I double checked the length of the TCA before re-tightening the two lock nuts(50nm). When the car was back on the floor I loosened then re-tightened the 19mm bolt to 80nm.




I took the car for a test drive and was happy with the result.

Now rinse and repeat for the TCA on the other side.

I thought it worth revisiting this thread to confirm that these bushes are still good.
After two years, the inner track control arm bushes are still without play and performing perfectly.

https://rimmerbros.com/Item--i-RGD000570PBOINNER

With the proviso that a few mm needs to be removed from the inner sleeve and the corresponding amount from the poly bush small end to allow the bush to fit into the subframe aperture, this is a good working solution to the perennial MOT failure of the rear track control arm.

Really useful guide. the steel tube is now the right length to fit in the subframe.