Spitfire Spitfire Rear Suspension

[JKB1957]

Need some advice. I have completely rebuilt the rear suspension on my 1966 Spitfire Mk2, new shocks, leaf spring, bushings, adjustable radius arms, hubs rebuilt, and the car sits with a pronounced positive camber. I have driven it a couple of miles since the rebuild and put 50lbs of sand in the trunk, but it still hasn't leveled off. Any suggestions on how to fix this, or should I just keep driving it until all the new parts settle in. Needless to say with the rear wheels tucked under it isn't a fun drive.

 

[Andrew Mace]

When and how did you tighten the bolts? Of course, it might be that the spring needs to (and hopefully will) settle. But it often helps greatly to either do final tightening of the vertical link, radius rod, shock absorber and spring eye bolts until the car is on the ground, or (much easier while the car is still securely on jack stands) use a jack on the bottom of the vertical link to carefully raise that assembly to approximate "road" position and then do the tightening of those bolts. That alone might just give you the proper "wheel attitude"!

Question 1: "adjustable" radius arms?

Question 2: Why did you replace the spring, and with what? A new "original" type? I'm sure it happens, but I don't think I've ever seen an early Spitfire spring "go bad"....

 

[71MKIV]

 

[JKB1957]

The car was a rusty wreck, so I did a complete restoration on the little Spit. The leaf spring was from Spitbits and is an original type. The adjustable radius arms I sourced from a company in England. I did this to do away with using shims. The entire suspension was assembled while the car was on Jack stands. I'll loosen up the rear suspension and see if that helps. Thanks.

 

[Andrew Mace]

It's probably a bit late to compare the old and new springs side-by-side, but I do wonder if the new spring might be a bit "overarched"? The original spring specs were 7 leaves, each leaf being .2188" thick (5.56mm); laden camber of 1.88" NEGATIVE, +/- .13" (38.9mm +/-3.3mm); load 945 lb.; rate 155 lb/in. -- if that data is of any use to you. :wink:

As I suggested earlier, the factory workshop manual states to "Place a trolley jack under the differential casing, remove the chassis stands and, with the vertical links supported at their running height, load the car and lower its rear end until the axle shafts assume their static laden operating position. This is to allow the rubber bushings to assume their correct working position before tightening the nuts [which, going by the accompanying diagram in the manual are the upper and lower shock nuts and the spring eye bolt/nut]. I would add to that the two radius arm nuts and bolts, since you've replaced that item.

I've had all too many opportunities, for various reasons, to R&R axles on my Herald in the last nine years. I've been doing the above, and I always seem to get a good slight negative camber in "static laden" position (book says 1.54" for the sedan; mine might even be a bit more). Oh, and it probably can't hurt to lubricate the spring as per normal maintenance recommendations. Seems to help on the Herald!

Oh, it just occurred to me: have you had the rear suspension realigned, now that you have those nice adjustable radius arms? That probably couldn't hurt!

 

[JKB1957]

Well I came home from work and slacked off the nuts for the rear suspension parts a half turn each. Went up and down the block once and the negative camber is gone! To be honest Nigel at Spitbits had suggested the same thing but I figured it had to be something much more complicated, and diabolical. I should have known, old British Sports Car, "keep it simple stupid." Thanks for the advise. Now it's off to have the front and rear aligned, and re torque all the nuts I loosened, and have some real fun driving this summer!

 

[Andrew Mace]

...I figured it had to be something much more complicated, and diabolical....

Oddly, that's a poor assumption with Triumphs! Often as not, it IS the simple things! Not like modern cars, where a fault with the power sun visor control module can adversely affect the variable camshaft timing, leading to total loss of all Sirius/XM station presets.... :hammer:

 

[71MKIV]

:lol: too true, too true. :laugh:

 

[Scott_Hower]

Not like modern cars, where a fault with the power sun visor control module can adversely affect the variable camshaft timing, leading to total loss of all Sirius/XM station presets.... :hammer:

Or where a bad TAILLIGHT ground causes the xenon/HID HEADLIGHTS to flicker and refuse to ignite.