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MG Midget and Sprite Technical - Now handles like crap.....

During the winter, I rebuilt the front and back brakes on my 1977 midget (US). Now that the car is on the road, it handles like crap. The car feels loose and wants to shoot off the the right/passanger side of the road (US car and roads). The car did not handle lick this befor the brake work was done.

I took the car to a garage for a front end alignment and to check my work that I did on the brakes. I was told the brakes look good. But the left side camber is at -1.5 and the right side is at -.5.

Would this alone cause the bad handling???

While working on the front brakes I replaced all the wheel bearings with Moss ones, and the suspension trunnion link bushings were replaced with the standard moss bushing set (not the adjustable ones). (FYI the trunnion is facing the correct way...)

The garage looking at it (which I do trust), suggests replacing the springs(normal hight). But I read here that replacing the springs (normal hight)would not affect the camber.

Should I buy the Moss 282-308 adjustable camber bushing set?

The car is kind of scary to drive now....
Any ideas would be great.....
Ken Samen (1977 Midget)

I re-check your work first... Clearly if the car was OK before you replaced the bearings, trunion bushes etc, then the error has been in re-assembly.

Don't buy anything yet... Check first.

Mark.
M T Boldry

<<While working on the front brakes I replaced all the wheel bearings>>

I would re-check those wheel bearings are right. Are they done up correctly. The excessive camber angle on one front could be a fault with the bearing, which would then also show up as skittish handling. With the front wheels jacked up off he ground you should be getting just the tiniest of rocking at the wheel rims, top and bottom and side to side. But little or none of this should be movement at the wheel bearing.

The other thing I would check is the toe-in
Guy

heck, a 1 degree camber difference from side to side is pretty much on par with what to expect from these car's build quality, and that alone shouldn't account for the suddenly poor handling (even of a 1500)

my vote is for toe (toe out will make the car quite skittish), but that should have been checked by the mechanic who just did an alignment!

if there is play in the wheel bearings, that could cause erratic handling, and could cause the toe adjustment to be incorrect if it was not caught by the mechanic. But loose wheel bearings should show up right away to any good mechanic who is looking for bad handling, so I am assuming that they were checked and were fine...

Leaving us with: what's left? Maybe loose rear axle U-bolts. Where the rear spring pads replaced last year when the brake job was done? If so, those nuts holding the axle to the springs will most likely need tightening up (which is usually needed, after replacing those rubber pads).

Norm
Norm Kerr

Norm,
My mistake - I miss-read Ken's message. I thought he had -1.5 and minus FIVE degrees! That's why I thought there might be a wheel bearing problem!

Toe in then.!

Guy
Guy

Yep Norm is correct the camber angles are well within the ABINGDON tollerance and I agree with him that the only thing that would be causing you a problem now would be loose u bolts on the rear axle.
this shows up most when acce;erating or braking when the car tends to steer to one side or the other
Robert (Bob) Midget Turbo

Thanks guys you are the best....

I rechecked everything on the front axle. I nudged a few things tighter. The wheel bearings have no play when pulling on the wheel. So besides that, I am unable to investagate them any further. I am sure I installed them correct (the wider rims/lips being in certain areas...).

But per Norm's suggestion, I checked the U-bolts on the rear axle (I replaced the rear springs a few years back). They were loose all around. I have tighened them up (Is there a tourqe rating for these bolts???), but am unable to test drive as it is now raining. Hopefully I will be able to give it a try tomorrow.

I thought the bolts on the u-bolt were locking. Should I add a second bolt to each tread, so they won't be able to back off???

Thanks again guys.....
Ken Samen (1977 Midget)

As no one else is around I'll post

Hope you didn't get the bearing excessively tight as I was told by guys that worked on the car 'back in the day' that they usually had a very small amount of play but I don't think you'd feel it if your pulling on the tyres (tires) anyway

U-bolts - no set torque I've seen quoted other than for thread and nut size, from Norm I think, just "tight as", but bear in mind the U-bolts may strecth anyway so don't go Hulk on them

It's just nyloc nuts (as far as I've seen)

Checked my U-bolts nuts as part of a service recently and two out of eight needed the slighest tweek after a year but could have easily been left
Nigel Atkins

Just Nylock nuts as per Nigel, though earlier cars used jamb nuts. The nuts don't actually back off, rather the rubber pads and the paint between the leaves squishes out. So retightening is a matter of routine maintenance, or any time the back end feels twitchy. Reasonably tight with a normal wrench for the bolt size, don't bend the bottom plate.

FRM
FR Millmore

being 3/8", grade 5 fasteners, the nuts want to be tightened to 35 ft-lbs, which can take quite a lot of turning to reach (the U bolts stretch a little, and the rubber isolator "sandwich" compresses a lot)

Use a torque wrench to make sure that you've hit 35, as there is a decent amount of resistance (around 20 ft-lbs) that gives mis-leading feed back for a long, long time.

Just keep turning.

...and go back a week later and re-check, a few times, until the rubber is finally, fully compressed/distorted.

I can see why racers use aluminum blocks here. Would probably make for a harsher ride in a road car, but a lot less "guesswork" for a racer.

Norm
Norm Kerr

"I can see why racers use aluminum blocks here. Would probably make for a harsher ride in a road car, but a lot less "guesswork" for a racer."

They take out any movement of the axle here. The difference when I upgraded from Nylatron spring pads was quite remarkable!
Deborah Evans

Norm -
" until the rubber is finally, fully compressed/distorted" is NOT what it is designed for. The whole point is shock/vibration isolation, and to do this the rubber must not be over compressed. It works too, but it does allow some axle "wiggle", at an acceptable level if all is correct. If you want it stiffer, use stiffer pads or eliminate them. Do not try to accomplish the same thing by over tightening the U bolts. 35lbft is seriously overtight.

General tables of bolt torques are for situations where you have no other basis for a torque, but are always superseded by system requirements. In this case, the requirement is that the rubber is under load but not squashed out, and the bottom plate is not bent.

In my experience, using new bolts with Nyloc nuts and antiseize, a standard 3/8 drive ratchet and deep socket will suffice, without undue force required. Really pulling on this combination can easily bend the bottom plate and deform the rubber excessively. Note that this is a prime case of tightening in a progressive criss-cross pattern.

FRM
FR Millmore

What tyre(tire) pressures are you running, I found after I fitted alloys and 155 tyres instead of the standard 145 that the car, 77 1500, was very loose at speed, even after rechecking tow-in and adjusting to 3/16". Dropping the tyre pressures to 22psi all round has improved it a lot
P J Vass

Echoing Mr. Vass, yes... check your tire pressures. Inflating Midget tires to the pressures usually used by moderns will result in very skittery handling. I run mine at 26psi front and 28psi rear. Harder pressures can send more road shocks straight into the springs and dampers. Tire pressures are dependent on the weight of the car, and in general, are meant to allow the tires to act as the first step in shock absorption; I got new tires on my Midget the other day, and the first thing I did was let the pressures down from near 40psi each to the 26/28 mentioned above... did that at the shop before even starting for home.

Cheers,

-:G:-
Gryf Ketcherside

40 psi sounds excessive but and if they were doing it they should have mentioned it -

IF I remember correctly in the past in the UK a tyre place might suggest over inflating the tyres a little for a short peroid when new

but as we now have a "litigation attitude" here too I guess they wouldn't any more plus tyre technologies changed

they should advise you to take it steady with the new tyres to start off with and to check/retorque after a set distance

you'll need an accurate tyre pressure gauge to check your tyre pressures

I don't have a copy but I'm sure the USA 1500 owners Handbook might have for normal use 22 psi front, 24 rear

for diffent tyres sizes, wall ratio, and even the fact tyres vary you can experment a little

with my 1275 I'm still on 22/24 or 22/26 if fully loaded and have always stuck to that but I'm going to experiment a little to see

at the moment I know if I forget to reduce from 26 to 24 at the back when not fully loaded on back roads the rear hops about a bit
Nigel Atkins

>>> 40 psi sounds excessive but and if they were doing it they should have mentioned it - <<<

Actually, 40-ish psi isn't unusual for many moderns. My MINI Cooper S runs 38 at all four corners.

Cheers,

-:G:-
Gryf Ketcherside

if that's the case I'd also worry about your nuts!

that is check what they torqued your wheel stud nuts to, should only be 45lbs/ft or you risk losing a stud or two

they should have checked with you the pressure for a model of car they don't know or have on their charts

they should have guessed there be a difference between an old MG and a new BMW or as I say asked

my wife had a little car with bigish wheels than needed 35 psi and I thought that was high (am I getting old? no don't answer)
Nigel Atkins

well, you have to consider that new cars are getting heavier and heavier. you need higher pressures to stop the tyres getting 'squashed' as much.

My Rover 25 takes 32 psi all round or 34 when carrying loads or driving high speeds for long distance.

Inflating tires reduces grip, as the tire bulges at the centre of the tread, thus reducing the size of the contact patch. It does therefore reduce rolling resistance (for the same reason) hence pumping them up for motorway journeys etc.

Malcolm
M Le Chevalier

my mate had a mid-nineties Jag and one of the ways to put it into sports mode was - increasing the tyre pressures, British fail safe technology :)

my wife's smart had tyres designed with a low rolling resistance for fuel economy and I think longer life

certain longer life tyres that can take our country's famous potholes and fuel economy ones are becoming more popular as the petrol prices rise and peak over here
Nigel Atkins

This thread was discussed between 07/05/2011 and 11/05/2011

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