Sunday, 21 March 2021

2021, February Life begins again!

 FHC Front Suspension Job

When I built the FHC a couple of years back it was in a bit of a rush so there was not time for some little jobs like modifying the front strut tops for the roller bearings. The best way is to machine a recess in the aluminium bells so the bearings fit inside them. There wasn't time for the machining work so I fitted the bearings without the recess anyway which resulted in a slightly increased the ride height by about 5-10mm.   Now I needed to have the struts apart to replace the "rubber" bellows which had split so it was time to do the bearing job properly.  

These gaiters lasted less than 2 years!

The most commonly used bearings used are a standard part from a Ford Escort Mk4 and cheap, part no. 6150276.

Ford Strut Bearings, part no. 6150276  

Background:  The standard TR7 strut top bearing is a plastic/nylon bush running against a greased flat washer. This may have been OK when new but over the years these have often dried out and many owners now find the steering too heavy for comfort. Power steering was fitted to some cars back in the day, mostly the TR8s in the USA market but this has two drawbacks, 1 it is for LHD cars, and 2 it is almost impossible to find nowadays.  Some folks have used a modified Rover SD1 power rack but the modern equivalent is an adapted version of the electrically assisted steering column used in many cars now.  The other easier and cheaper option is to just fit the bearings which do the job perfectly for me. 

 The standard strut top parts look like this:-

1. Spring top pan

2. Nylon bush/bearing

3. Rubber seal (runs outside of 2)

4. Flat steel washer (runs on top of 2)

5. Aluminium cone (goes on top of 4)

6. Strut top with rubber insert

7. Cupped washer 

The new bearings replace the nylon bush (2) and the flat washer(4).

Like I said above, when I built the car I just put the roller bearings in place of the nylon bush but being much thicker they do raise the ride height so I wanted to fix this. 

Thickness of the Ford bearing

 The way this is done is to machine a recess into the aluminium cone to take the bearing with only the running surface being slightly proud of the cone, like this:-

Modified cones to take Ford bearing (photo Beans)

Putting it all back together with the well geased new bearings and new strut gaiters was pretty easy, not forgetting to include the bump stop on the damper shaft.  There are various options with the bump stop, some folks don't use one at all (not a good idea!) and some have the nice expensive polybush version.  I just use a cut down rubber one as suggested by Steve Wilcox of S&S Preparations.  The new standard ones sold now are too long.  All you need is one (yes one) rubber bump stop and cut it in half, so it does for both struts. Result!

Half a rubber bump stop is used

With the car back on its wheels I took it for a quick test drive and the steering feels excellent, light and precise - and back to the proper ride height.  

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