Lotus Seven and some Caterham 7s fitted with the cast Track Control Arm

[EdWills]

What is a suggested replacement when the ball joint in the cast track control/top arm/top link (all names used by Lotus for the same part in the Series 2 manual) wear out?  The same goes for owners of the 1000+ Lotus Type 14 Elites, which used the same track arm.  On the Mk.12/Type 12 racing car, Lotus modified the Ford tubular lower track arm from the 100E and Consul by cutting off the end and welding in a threaded sleeve to take an adjustable ball joint.  Ford then produced a cast part for the 100E/Consul, so Lotus produced their own cast top arm for the Elite Type 14 and the Seven (Tony Weale advises that this part is one of the few original parts for the Seven from 1957 and his book details the above).  

 

I checked on-line with the Lotus Elite 14 forums, but no one mentioned the part.  A company in the U.K. somehow manages to replace the ball joint inside the original housing, but they only do this once a year according to their site.  Lee Chapman used to carry this item, but no longer on the web site, same as Tony Ingram, and others (Bean, Caterham, Kelvedon Motors U.K.).

 

Recently on ebay.com, a pair of very used Lotus Super 7 top links was selling for $445.00 U.S. or $613.00 Canadian.  The rubber gaiter or sleeve was missing from the ball joint, and the arms looked rusty and well worn.  The item sold with an offer, but the sale price is not known.  What will owners of Sevens/7s do when the ball joints in these arms wear out and become a possible driving hazard?

 

Perhaps the purchaser of the used arms has a plan to go back to the drawing board and manufacture some tubular replacements?  It could make sense if the arms are well made.  There is not much space between the ball joint and the opening that allows the anti-roll bar to fit inside with the rubber bushings, so any threaded ball joint would only have so much thread to allow adjustment, or to be welded/brazed inside the extended tubing.  Food for thought?  W.

 

 

[7Westfield]

If I was going to make a tubular arm, I'd look at making the tube full length, with a tie rod end as the outer joint.

Put a loop above or below the tube to accept the sway bar bushings

Would need to replace as a pair to avoid twist in the sway bar

Not a visual match, but should work fine

[toldfield]

Check with Chris ...

 

http://www.sevenselans.com/sevens_home.htm

[joe7]

What will owners of Sevens/7s do when the ball joints in these arms wear out and become a possible driving hazard? I also had that concern. So, I bought a pair of NOS track control arms. Unfortunately, I sold the 7 before I need them and still have them.

[EdWills]

20 minutes ago, joe7 said:

What will owners of Sevens/7s do when the ball joints in these arms wear out and become a possible driving hazard? I also had that concern. So, I bought a pair of NOS track control arms. Unfortunately, I sold the 7 before I need them and still have them.

Hi Joe.  Hopefully someone on this forum will grab them before too long, if not, perhaps try another Lotus forum.  I understand that the Lotus Elite type 14 owners have a dedicated site that can be reached at http://EWROwners@comcast.net

 

W

[MV8]

I don't think any welding would be required though a stitch could be added to the press fit. I'd probably press the old joint from the arm, machine a press-fit bushing (to replace the old ball joint) that accepts a standard spherical insert (see mcmaster for examples), machine/purchase a split taper insert to tap into the top of the knuckle (left slightly protruding when fully inserted), add rubber seal washers top and bottom to the new, spherical insert, then fit a high carbon bolt to hold it together. Besides standard wear parts, the knuckle length would now be adjustable.

 

 

[EdWills]

3 hours ago, MV8 said:

I don't think any welding would be required though a stitch could be added to the press fit. I'd probably press the old joint from the arm, machine a press-fit bushing (to replace the old ball joint) that accepts a standard spherical insert (see mcmaster for examples), machine/purchase a split taper insert to tap into the top of the knuckle (left slightly protruding when fully inserted), add rubber seal washers top and bottom to the new, spherical insert, then fit a high carbon bolt to hold it together. Besides standard wear parts, the knuckle length would now be adjustable.

 

 

Hi MV8.  Brilliant idea to renew the ball joint.  Didn't think of that, but it would work.  It would make a sound unit that could be renewed as necessary. W

[IamScotticus]

Can we safely assume the ball joints are Spitfire/GT6 items?

Would it not be a press out and replace proposition? 

Pressed out of this?:

https://mossmotors.com/661-095-ball-joint

 

For $15 dollars, I can tear one up to find out.

Edited August 21 by IamScotticus

[MV8]

Yes, I think it would be the correct balljoint. I don't know how much of the grip to the housing is due to the rivet-like assembly versus a press-fit. A new tubular arm could have flanges to use the standard spitfire ubj if there is enough room.

[MV8]

What I described previously:

[EdWills]

On 8/18/2025 at 8:50 AM, 7Westfield said:

If I was going to make a tubular arm, I'd look at making the tube full length, with a tie rod end as the outer joint.

Put a loop above or below the tube to accept the sway bar bushings

Would need to replace as a pair to avoid twist in the sway bar

Not a visual match, but should work fine

A company in the U.K. producing parts for the Lotus Elite type 14, (enquiries@mk14components.com part #FS02) has just finished machining a batch of reconditioned track arms for some of their customers on an exchange basis.  As suggested by MV8, they machine out the old ball joint, but replace it with a new removable ball joint assembly that can be changed for future repair.  However, they advise that this process is very expensive, and they have been losing money by doing this.  They are considering remanufacturing the cast part themselves, but prices will rise.  Right now, they charge 375.00 U.K. Pounds Sterling (without tax) on an exchange basis for a pair of reconditioned arms.  

 

Regarding @7Westfield's accurate assessment (thumbs up to you), they are producing arms as shown in this attachment.  They feel that it will be aesthetically o.k. for an Elite, as the bodywork covers the front suspension, but on full view for a Seven if authenticity is not a problem.  Also, cheers MV8 for the diagram. W

Edited August 21 by EdWills

[MV8]

With the tube below the arm, the tube should be welded slightly inboard from where it was since the front arm end will be further inboard (to prevent push-pull on the rear arm) and the car jacked for the suspension to drop to align the end of the sway bar (some preload will be created at ride height) but not a big deal imho.

[jbcollier]

Mine were ok: torn boots but the joints tight.  I drilled them for grease nipples -- not very effective as there are no grooves for the grease to flow through -- and fit new boots retained with wire -- old boots were slip-on and now hard to find.  I bought a set of replacement arms from Mike Brotherhood against the evil day when the joints are worn.  They are the usual replacements with adjustable camber.