MK IV leaf springs

My 1948 Mk IV 1.5 litre would probably benifit from some new rear leaf springs (as certainly one is not correct, and I would prefer to change both at the same time). I have the written specifications for the part number C.195 but does anyone have a Pattern or Drawing Set for these springs?

IMG_20200826_082406 IMG_20200826_082352

I have a local spring company willing and able to make them, but they would prefer to have working drawings to make sure everything is as original as possible. The alterative is for me to first remove mine off the car - but that will mean it’s laid up in my workshop for some time!!

Hi David,

I don’t know the location of any detailed dimension drawings but if nobody else can help you then it might be best to let the spring manufacturer have your’s as a sample. I know of another MkIV owner (3.5 litre) who had new springs made for his car and they were far too hard. You could imagine that you were driving without any springs at all. I may say that this was at least 40 years ago and he no longer has that car so I think it highly unlikely that he still has drawings. Not that you would want to replicate them.

Peter

I think Peter the 3.5 litre has different spring sizes to my 1.5 litre. If I can’t get any drawings then I will have to make some as a traced pattern off one of mine when I get it off the car. I have been considering trying to find a similar 42" length spring, even with say just 8 or 7 leaves as I know the “springiness” of custom made ones can be totally different to original (or somewhat worn) parts. If anyone knows of a similar size spring set from another car manufacturer of the era other than Jaguar then please let me know - something standard off the shelf is bound to be lower cost than custom made!! Knowing the Jaguar factory they probably shared such parts with other car manufacturers to keep costs low.

I think with taking a few measurements of the correct spring, you have enough information there to create your own drawings.
Width of the material is 1.75" or 44.5 mm.
Thickness of 9 leaves is 1.75" so dividing by 9, one leaf the material thickness is 0.1945 or about 5 mm. They probably used 3/16", as they would have used some commercial standard rolled steel thickness. You can measure the thickness of the top leaf, and they should all be the same. The depth might include allowance for a bit of curvature, or they were lazy and just didn’t record the actual depth of 1-11/16", figuring nobody would ever make their own springs.
You can measure the length of each leaf from the center bolt to each end and add them.
Free camber on the rear means a measurement to the center of the top leaf from a bar laid across the leaf ends. It is a lot, which is why you need the special hook tool or a lot of strength to replace them.
Are your leaf ends rounded and tapered? Mine are on the Mark V and XK120, but on the '38 SS they are just cut off square.
If you get all that information prepared, the spring shop can order the material and get prepared in advance before you bring them your spring to match up.

My springs are all tappered both ends on each leaf (front and rear spring sets) with the same style of shackles throughout.

I will do some measurements and make a drawing when I can get my MK IV back on my workshop car lift (at the moment I’m working under one of my other cars). I’ll have to remember how to use a pencil, paper and protractor again!!

I’ve not got Jaguar’s spring removal tool so I will have to think of a good safe way to remove and re-install them. Any suggestions of practical experience for removing them?

You really need something like the special tool when you are working on a bare chassis without the weight of the body on it but it’s much easier when you can use the car’s weight.

Peter

Has anyone come across a source or supplier of one of these spring removal tools? I don’t think I would risk making my own in the workshop as the tensile strength needs to be good for the job.

Anyone tried more modern spring compressors or jacking tricks?

Jacking is the answer.

Peter

Hello David, can you describe what is not correct about your springs? Is the incorrectness something which cannot be fettled by refurbishing existing springs, e.g., re-arching by means suited for the problem?

In an earlier post I put on the forum I asked for advice in raising/lowering the ride height as I had a slight rear end lean. However I found that one of the rear springs was in fact a 10 leaf and not 9 leaf as it should be - maybe off a 2.5 or 3.5 litre and not for the 1.5 litre. So the problem is I need a new correct spring (which should then level the rear end I think) but I feel I should replace both sides at the same time. Copying the one corrrect spring I have seems the most logical solution.

I have one, but shipping to Jolly Olde may prove more expensive than getting one there.

Here is how I did it, with a chain and a long pry bar.




I see that my springs have shorter leaves on top and bottom, a different construction to later models.
I forgot to mention that you will need holes in some of the tips where the clamps are riveted on.
Here is my Mark V spring with rounded tapered ends.
IMG_20200826_140156501

It’s a long time since I did this but seem to remember changing a front eye bolt. With the rear shackles all connected up it was possible to position the leading end of the spring by jacking to get the right degree of curvature such that the front eye was correct fore and aft and it was only necessary to lever it down to get the eye bolt in.

With no body weight to jack against you do need something like the special tool and a very long lever.

Peter.

Gents
This is the spring compressor I made up and used on our 3.5 litre (MKIV) rear springs , makes the job relatively easy.
Regards
David
Spring compressor

Be real careful. A few years ago I was removing the underslung springs On my 1946 Chevy street rod, the sprung, sprung catching a finger between the spring leaf and the cement floor. The finger went SPLAT and there was blood and skin tissue all over. Not a pretty sight! Finger healed but the bone was crushed and healed funny…but now it goes with the rest of me! :crazy_face:

I might see if I can make a similar compression tool to David’s photo as this could be a safer option in the removal and refitting process.