Getting the best out of standard suspension components for touring driving today

Wellllll… maybe.

All the rubber bushings in Tweety, a 1963 car, were still in serviceable shape. I replaced the front stuff when I rebuilt/cleaned the suspension as a matter of course, but they weren’t really in very bad condition.

Likewise, all the rubber bushings on my 1967 Rover are in actually quite good condition. Perhaps, by the time they got to the Arnage, they were using less than good quality bushings, but the metalastic stuff on series 1/2/3 jags was actually very long lasting.

None of this is to say that PU is bad: I don’t think it is. But as it was pointed out before, not all PU is created the same. I think some people tend to go for the very hardest stuff, and then find that that gives a very harsh ride.

Hi Paul…Long lasting original Metalastic…probably depends on the car…how it was used…climate…age etc…when i got my UK 69 2+2…it was 40 years old…only had 50k miles on it but a UK car…obviously driven on our salty winter roads and the suspension covered in grease and oil…rubber dosnt like oil…anyway all the bushes were shot…and needed replacing…original metalastic were no longer available…so Polybush went in…Steve

The bushings on my XK140 were well beyond saving when we replaced them in the early 2000s (with the red poly bushings supplied by ClassicJaguar at the time) I expect usage, storage conditions, etc have a big factor regardless of material.

With the Arnage my understanding is the originally spec’d the suspension for the 4.4L BMW sourced engine, but the front end gained ~600lb when they reverted to the 6.75L v8 + GM 4L80E transmission combo.

Well, somehow, that doesn’t surprise me: I had a friend of mine, who was a master technician at a BMW dealership up in Boulder: during that particular era, he said that BMW became known as, “Balance My Wheels” again.

He told me that the bushings on the cars were absolute junk from the get-go.

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I will need to purchase suspension bushes in then near future. Are original metalastic equivalent ones available new or does the choice boil down to aftermarket cheap bushes, polyurethane bushes or searching for nos ones ?

My two cents is, if you can find Genuine original metalastic bushings, they were the best.

I would add that if you go for the PU solution, don’t install the stiffest ones.

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Hi Geoff. …the original Metalastik company is no more…Trelleborge have taken over the name i think and manufacture metal bonded rubber bushes …a quick google search will also show you other “Metalastic” bush suppliers…Martin Robey (jag spares supplier) do sell bushes with “Metslastik” stamped into the “rubber”…so are whats available now the same as the originals. …who knows. …Steve

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I had a quick look at an Arnage parts diagram, the rear bush looks to be voided, possibly hydraulic? If so, I’m dubious that a simple rubber or PU bush can reproduce the refinement of the original. Might be acceptable relative to the USD 460 price tag though :scream:
It seems the fixings are eccentric, presumably to allow alignment adjustment. Could that be a factor in their durability?

Looks like the front bush may be stiffer for cornering loads, the rear softer for ride isolation. Wish I’d thought of that. :upside_down_face:

Some good general reading about various bushing options.

I’ve never seen Autopian before, they seem to go a level or two beyond the average “real man makes everything stiffer” article.

Steve will note they don’t distinguish the Polybush style of PU installation from the more typical setup with relative motion between the surfaces.

Something bothers me about that aspect of PU. If the overall stiffness is similar to rubber bushings but they slide in more easily, does that mean the installed radial preload is lower with PU?

I generally favour bushings with an outer sleeve giving some built-in preload, I think it gives a little more precision to the ride and handling. I’m not sure I’d be brave enough to press one into the Jaguar danglers though.

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That they slide in more easily tells me the control arm eyes must rotate around them, negating stiffness & affecting overall damping & spring rates.

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I bought the stock bushings for my car and plan to put them in soon. I’ve read about problems getting the old ones out and new ones in. I don’t have a large vise to use but I do have access to this old school press. It’s been sitting in the back of a hangar for decades. I’m sure the mechanics would let me use their hydraulic press but, I’d prefer using this old heap if I can.



Looking at how mangled the top of the sliding part is, I wonder what in the world they were doing with it.

Same, as with the top of my Dake arbor press, which is virtually identical: you have one person hanging on the 4-foot-long bar, and another person whacking the top with a sledge!

I had a whole host of jigs that I had ginned up, to do such things like you are doing.

So as beefy as they look, they really can’t apply significant pressure compared to a hydraulic bottle jack type press?

That depends on the size of the bottle jack! If I recall correctly, an arbor press like that can provide up to about 8 tons of force.

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That’s the way the stiffer PU bushes are said to work. Steve says in the E-type application the Polybush is soft enough to locate on the arm so the PU material twists with suspension travel, like a rubber bush

I’m making a better test fixture so I can test the effect of different mounting hole diameters on the rates of various bushings. (The Polybush is about 0.5mm smaller diameter than the Jaguar and Robey rubber bushes).

Hi Clive…lets not get confused here with the Bentely discussion as we have no idea what PU bushes are being mentioned…just to confirm here im refering to E type only…and only the Black bushes manufactured by Polybush…yes they are designed to fit and work in exactly the same was as the original style bushes…they are shown here
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SNG Barratt UK | Keeping your Jaguar on the road
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Yes, I’ve amended my note to avoid any doubt there.
Cheers

We await some test results, should settle it.

I await a 33mm cutter to upgrade my test fixture