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MG Midget and Sprite Technical - replacement of front lever arm suspension

Dear All,

I am about to replace the pasenger side lever arm suspension. the manuals sugges that this is simple road wheels off, suport wish bone pad with trolly jack until clear of bumpstop, then four bolts and off, in experience is there anything else i shoud be wary of.

regards

Doug
df mccabe

the only other catch is whether the inner pivot bolts come out of the frame for you, or not. They often seize in place, unless the previous mechanic used anti-seize before assembly.

A hack saw is your friend, in that case.


Norm
Norm Kerr

Doug

There are books on this... I'd suggest supporting both chassis arms before you start.

In essence, all you have to do is undo top trunion bolt, tre, 2 calliper bolts, disc shield bolt, 2 inner wishbone nuts and remove bolts(*), cotter pin(*), unscrew bottom trunion(*)...

(*) items are the interesting ones... take a look in the acrhive

A
Anthony Cutler

How do you interpret the question guys?
I think the OP is *only* replacing the shock absorber...
David Smith

I wondered that also David?

Doug are you simply replacing the lever arm shock absorber?
Bob Turbo Midget England

meh - it's a midget - whatever he's replacing - he'll end up having to do more rather than less ...!!!!
rachmacb

If it is just one front lever arm damper then -
Jack the car and support on axle stands under the chassis legs.
Jack the spring pan until the arm lifts off the bumpstop.
Remove the pinch bolt
Remove split pin and the trunion to lever castlated nut.
Remove the three damper to chassis bolts.
Lift damper off.

Replacement as they say in all good? manuals is the reverse. Make sure the trunion is not turned 180 degrees unless you like lots of positive camber.
You may also need to remove the heater trunking if it is the driver side damper.
There isn't much more to it than that, but why are you only replacing one? I have been brought up to believe that you alwasy replace suspension in pairs.

Good luck

Dave
D Brown

Hi David

I saw 'replace lever suspension'... as opposed to lever damper... but you may well be right!

A
Anthony Cutler

Many comments here:

1. Normally, dampers are replaced in pairs so you have balanced response on both sides. Dave's spot-on. If one damper is worn out, the other might not be far behind. And since these components are an integral part of your front suspension, and can adversely affect both handling and steering, I'd play it safe.

2. Even with the car supported under the spring pan, there may still be tension on the spring. I always remove each spring when replacing the dampers. Different people use different methods, but I prefer to let the springs out through the pans using a pair of long bolts (6") through two of the spring pan holes, diagonally opposed, each with a spacer and nut underneath. Just undo the nuts in turn, a little at a time, until the spring is completely relaxed. Others prefer to jack up the end of the lower arm, remove the castle nut and trunnion pin at the top, and then let the jack down to relax the spring. Whatever the case, you don't want ANY tension in there when you take out that upper trunnion pin, at the risk of hearing an almighty bang...

3. When reassembling, you need to make very sure that the notch in the upper trunnion pin is correctly aligned with the pinch bolt hole in the end of the damper arm. And the last time I replaced dampers - just a few days ago - I ran into a tolerance problem where there wasn't quite enough clearance for the bolt, and I ruined two of them before taking the pin out and slightly deepening the notch with my Dremel.

4. Use new split pins to secure the castle nuts. For that matter, you may find that the rubber bushes at the upper trunnion are perished, in which case the trunnion pin itself may be damaged. Inspect this area carefully, since any wear here may cancel out the benefits you'd get from new dampers, and you'll still have handling issues. Many of us have replaced the rubber bits with polyurethane for a more positive connection and greater durability.

5. Note too that with the upper trunnion disassembled, you may be able to feel free movement at the lower trunnion (meaning, the kingpin/hub assembly will be free to rock forward and back). This indicates wear in the lower trunnion pin/wishbone joint, and if it's really excessive, you may be looking at a lot more work.

6. The shop manual says that the six damper bolts should be torqued to 25-30 lb ft, but they're buried so deep in the engine bay that it may be difficult to get a torque wrench on them unless you have a long and robust extension. (I.e., one that won't twist and muddle the torque reading.) I confess that when I did my dampers I just tightened the bolts up nice and firm by hand - sort of a seat-of-the-pants method. I used all new bolts as well.

Sorry to throw cold water all over the discussion, but front damper replacement can actually be a pretty big deal. There are safety factors involved while doing the procedure, as well as once it's all complete and you take the car out on the road.

Best of luck. Wish I could come over and help... Scotland must be nice this time of year!

Cheers,

-:G:-
Gryf Ketcherside

Oh yeah, more on removing springs... if you use the long bolt approach, begin by jacking the suspension up under the hub (not the spring pan... you need more leverage) until you can stick a block of wood about 1" thick between the damper arm and the chassis, just inboard of the rubber bump stop. When you let the jack down, the wood will then hold the suspension up in the optimum position for the spring to release.

As for aligning the notch in the upper trunnion pin, this is a fiddly process of looking into the hole to see the notch, tightening the castle nut to draw the pin into the damper arm, and rotating the pin via the hex head on its aft end. Once it's all aligned and the pinch bolt is installed, you can then snug up the castle nut and pin it.

Also inspect the trunnion pin to make sure it isn't damaged due to a bad bush, corrosion, road grit abrasion, etc.

Sigh... you can tell I've done this recently. ;-)

-:G:-
Gryf Ketcherside

Hi Gryf very welcome to join me but weather in scotland is shocking at present which gives as good a reason as any to stay home and work in the garage.

Fo the sake of clearity it is only the shock absorber passenger side (Left) for those state side.

I was my intention as this side appears shot to replace with what i think is an original part (unipart) label on the part came with the car several years ago, should i wait and replace a pair. i can see this as an ease fix as these only cost about £50 a pail reconed and another £20 for the polybushs?

ta again

Doug
df mccabe

Hi Doug,

I would definitely go for replacing the dampers as a pair. I recently attempted to replace mine with 'uprated' recon dampers. I only got as far as removing the NSF damper and ended up putting the original damper back on. I used the approach suggested by Dave with no problem with the method. The problem I had was with the dampers. One damper had been repaired with a helicoil which was starting to come unwound (and I felt rather unhappy having a helicoil in the suspension in anycase) and the other damper had actually started leaking in the box before it was even fitted. This had 0 resistance in one direction and I could hardly move it in the other direction. I guess avoid cheap recon dampers is what I am trying to say! Peter May ones are supposed to be good, but I have not tried them personally.

I also removed and refitted the wishbones recently and the 6 inch screw method works a treat to release the spring if you want to go down this route to damper replacement.

Tony
TonyJHamilton

Replace as a pair
Actualy that can be said for most suspention and brake parts.
Unless there is an verry obvious reason to do just one side do both.
Onno Könemann

Following on to Tony and Onno, experience will show that with a car as old as the Midget, digging into one fault will usually turn up others. With suspension bits being exposed to all weathers, plus corrosive road spray, the hostile working environment takes its toll. I remember when I ordered poly bushes for my rear spring shackles... I assumed that I could just swap out the rubber for poly, but when beginning to remove the first shackle, the nut wouldn't budge; and when I applied a bit more grunt, the pin snapped off. Then when I got the things apart, I saw that with or without the broken pin, I needed new shackles badly, as the pins were very rough. The rubber bushes had perished, allowing metal-to-metal contact. Those things would have eaten new bushes for breakfast...

So again, when you're working on suspension:

1. Assume the worst.

2. Replace all related hardware; pins, nuts, bolts, etc.

3. Do both sides at a time.

Cheers, and keep us posted!

-:G:-
Gryf Ketcherside

This thread was discussed between 19/07/2010 and 20/07/2010

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