Another well presented lesson. Accurate steering geometry is one of the most sophisticated and difficult engineering concepts to achieve or even grasp. It’s high-speed ever-changing three-dimensional mechanics over infinitely variable surfaces. And your gravity car is a great showpiece for steering. Especially the Ackerman Steering Principal, which you did not mention, probably because it’s a calculus course in itself. Thanks.

That was a brilliant explanation of how the unequal length wishbones work.

Hi, John, Just a note for anyone needing a new top wishbone, I found the best place to be Autoreserve parts in Ilkeston, Derby. They advertise on eBay but if you call them direct the price is much lower and they will refund £120 for your old one if, unlike me, you're lucky enough to get your old one out in one piece! Cheers Paul

An excellent lecture from Professor John D. from the University "to the Garage". The students thank you. 😂

A great informative video John. Thanks.

Hi John, I can see this video, and your upcoming / previous videos on the suspension being very handy soon when I get stuck into mine mate 😮

Congrats John on another excellent 'explainer'. I think (hope!) my Jags' bushes are all ok (though I have some slight doubts about the front subframe rubber mountings on the XK8). However, I ordered all new lower front control arms and bolts for my daily yesterday and hope, over Christmas, to find time to do them both as well as a rear wheel bearing, so as ever, this was interesting and relevant content. Best wishes to you, Jo and the family for Christmas and New Year and see you in '24. 🥂☃️🌲🎁🎄🎅🏎️🚘

Thanks 👍

Great video John. Really looking forward to this series 😁👍

Hi John, very informative, every day is a school day…. Thank you

Thanks John, really excellent coverage which will help my suspension knock.

John's driving me around the bend...How did Ackermann get left out of the discussion? The rest was excellent. Not quite on the shims. They only go between the bushes and the crossmember. See my XK8 Bible for more detail.

Hi John - just wanted to thank you for another informative video. I'm 18 months into XKR ownership and absolutely loving it. The suspension needs attentiin (I think) so these insights are really useful as I build confidence on it.

Great explanation again John. I embarked on changing all my bushes and ball joints last year. Your video would have helped so much with the whys. Why did Jaguar do it this way. I managed to do everything myself and as you say, a press is a must. I did have a few issues with pressing in the bottom wishbone ball joint due to its peculiar shape, so I'm really interested in how you tackle that on future videos. I'll share with you my crude but effective method of getting those babies back in. Keep up the great informative videos!

hi john love your vids but I have some criticism but please understand its for contributing to your great channel and not to troll you in any way. so the yellow washers are called dimple washers and they are dimpled to hold the grease to allow them to slip. as our jaguars age with time re greasing these washers is a good idea and worth a mention. also you are incorrect about the pivot bolt. the pivot bolt must NOT turn in the aluminium sub frame. this will cause ware on the subframe and and then you will have big problems. and just to add to your channel if I may. 4mm of shims is 1 degree of castor. there is a lot of talk about having to put shims back perfectly or it messes up the handling that's a bit extreme, its just very time consuming getting them right to take up the slack. if you convert to polybush then you don't have this problem as there is nothing solid to clamp on. but the original jaguar set up is clamped on to the tubular washers that are supposed to slide around the bolt. hence these need greasing too and hence you cant have any slack and need a series of fine washers to get it right. some washers are less than 1/4 mm thick. you need to have 1 degree less of castor on the side of the car that rides in the middle of the road and you can set the side of the car that rides in the curb to what you desire as long as it allows for the other side to be 1 degree less. YES !!!!! I know its best to set up to jaguar spec but if you set up to different specs and test drive the car you will know why i am saying what im saying. i set my 1999 XKR so that the upper wishbone curb side ( passenger side ) was as far back towards the rear of the car as possible and then on the drivers side i set 4mm of shims to allow the 1 degree of castor difference and then used 16mm washers i sourced from the internet to take up the slack. this can take time but it is do able. hence I understand why people say make sure you remember how all those little shim ( washers ) cam off in order as it will save you time . there is a lot to say and i have tried to keep it short but happy to talk in more depth about it if you wish. can not say enough how much i Love your channel and hope this is accepted in the spirit it is intended.

Excellent explanation John, loved it. Is there any harm in giving the upper wishbone bolt a squirt of WD40 when the opportunity arises, to reduce the chance of seizure to the steel bush pivot? Hope not cos that's what I've bin doing! Looking forward to the next episode - hope you have some heating in the garage!

Love the garage cheers john my 2002 my need new diff its got slack in it do you know any were to get recon

Evening John.

Top wishbone 'pivot' bolt requires a torque of around 110 Nm. When I tighten the nut to that torque, the force is concentrated on the bush inner sleeve. What happens is, the 'thrust' washer, which is directly in contact with the sleeve, gets deformed to such an extent that it is more or less 'rivetted' to the pilot bolt and subsequent removal of the pivot bolt is impossible without removal of the crossmember! Surely, this is not designed but I do not want to drive the car with less than the Jaguar recommended torque setting but my car has been off the road since front suspension rebuild. Can you help please?