CAV GT40 ball joints


Hello guys, simple question that should have a simple answer..

I have an early pre-100 CAV GT, and i'm busy revamping the suspension front and back. All rod-ends were worn, some seized, rubbers tearing, etc.
Also the wishbones themselves have developed quite a bit of corrosion, so I stripped them for powdercoating.

Now: I want to take that oportunity to replace the ball joints with new, since some of them are corroded as well, but I can't figure out what make/model they are off of.
Is there anyone that has the answer? I saw an older post claiming they are BMW E30's, but according to my spare shop's books, the taper on those is quite different and is not the same thread size.

Hope this body of knowledge can answer this simple question

thanks, Jasper


Just to keep you guys in the loop. Been hunting for a good few weeks now, but still drawing absolute blanks.

All I know is that its a 1/10 taper, an M14x1.5 thread, and a 45.5mm press fit without circlip.

Just amazing how this information is not out there anywhere.


I did of course, but he's not helping. He claims to not know because its a pre-100 car. (i.e. not his production cycle, not Jean's.). However, from what i've seen it might very well be all the same thing.

Absolutely perfect Bill!! That's something to go buy. Partquip is a well known parts supplier in South Africa, so with that number I should be able to get some! Will let you know how that goes OK?

Mike Pass

Ford Cortina Mk3/4

Quinton Hazell part numbers
Upper QSJ662S equivalent to MBJ662
Lower QSJ663S equivalent to MBJ663
Get them locally or Southern GT or Wealden Engineering in the UK will have them.


Mike, these BJ's are bolt-on (meaning they are supplied with a plate). Are you sure your info pertains to CAV GT's?
Hi Jasper, the CAV ball joints were used in both series100 cars and post100 production. I don't know when these replaced in recent years or are in fact still in use. I can stay the ball joints are reliable and capable of considerable abuse, ie: lower ride height will bind the upper joint in bump and bend the pin. The boots are susceptible to splitting if run in bind or during removal for service replacement or upgrade. You should be able to purchase these in SA. Here's the part numbers. Cheers



Thanks Ian, thats great help. Can you explain the upper joint to bind in lower ride height in bump? Which side are you referring to, top or bottom? It seems a bit weird for an any to bind in low ride height when in bump. You mean in further droop?

(sorry late reply, didn't notice your comment earlier!)
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Hi Jasper, The upper ball joint at normal ride height (5 inches for most KVA / GTD based cars) has 7 degrees of the movement in the joint is being taken up by the kingpin angle of the CAV upright, leaving about 7 degrees left to use in bump. If you drop the ride height to original GT40 specs (4 inches full wet) you lose another 3 degrees due to upper control arm incline, now you have about 4 degrees left for bump, you'll use that up in about 1 inch of upward travel in bump. After that you're binding the pin.
The CAV GT is a very robust car. The ball joint pin will bend before any damage to the upright assembly or upper control arm. Ball joint pins are machined from alloys designed to do just that, bend rather than break off. On the CAV Canada suspension upgrade kit the ball joint issue was fixed along with revised geometry to reduce bump steer, improved ackermann for corner entry, reduce rate of camber climb in bump to keep tires level with the road, CNC machined steel hub carriers to stop premature hub bearing failures and save weight were introduced. The upgrade kit was designed for dual purpose cars, street and occasional track use on lapping days. Totally transformed the car.


Last time we spoke (email) you mentioned you're currently not making and selling these anymore/yet, due to some work on welding jigs etc. What's your current position on your upgrades? Uprights and arms.
There is renewed interest in these parts particularly from new CAV owners like yourself looking to build or upgrade older CAV GT40s to the best it can be.

I am always happy to help out with advice regarding technical questions raised by forum members regardless of brand of manufacturer as there are many common challenges. It did take quite a while to hunt down those ball joints however...

As for any new parts offerings, it would be inappropriate to discuss that here before becoming a Supporting Vendor of the GT40s Forum again. Back in the day when these cars and parts entered the market Cape Advanced Vehicles and CAV Canada were Sponsor Vendors.

Cheers Ian