Hey Eric,
The purpose of using these types of bushings is to reduce or eliminate
bushing deflection under cornering loard. This helps the suspension
maintain it's geometry better which provides for more stability and less
camber loss in a corner.
The trade-off is in the reduced isolation of road harshness. The setup
I use is urethane bushings on the A-arms and nylon on the upper
fulcrums. I don't think the urethane bushings transmit that much more
harshness than stock, but they are much better at properly locating the
arm and do not bind like stock bushings allowing the A-arm to move more
freeely. This allows for better tracking of the road surface.
On the nylons, there is a trick to making them work right. When the
instructions say that "some hand fitting may be necessary," they mean
it! If you just force them into place, they'll bind quite a bit and
your ride will be very harsh - not to mention that you've just ruined
the handling of your car.
Hone out the center hole until the upper fulcrum pins fit and turn
perfectly. You'll also need to sand the outer mating surface where they
slide into the upper end of the kingpin so they fit perfectly.
Remember, do not overtighten the castellated nut, or that will induce
binding as well.
Also, LOTS of grease on the fulcrum bushings and on the A-arm bushings
is mandatory.
On the back leaf springs, the stock eye bushing in the front is fine,
leave it alone. More positive lateral location of the rear end can be
achieved by using either urethane or nylon shackle bushings. Same rules
apply here as with the front suspension, otherwise, you'll have
problems.
Hope this helps,
Andy
'67 BGT Vintage Racer - in pieces
'72 B Roadster - in more pieces
Eric Zambori wrote:
>
> What is everyone's opinion Pro and Con concerning the use of
> Polyurethane bushing for the front end of an MGB. I've heard that the
> Nylatron bushings that Moss sells are way too stiff for street use and
> I've read several threads regarding the harshness of polyurethane when
> used on the rear leaf springs. But I'd like to know what to expect if I
> replace the lower control arm bushings and the upper trunnion bushings
> with polyurethane.
>
> THANKS
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