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This is not my car. I am helping a friend with the suspension on his '78 Mini 1000.

He wants to install new rubber cones and a set of Hi-Lows. The method I used on my '64 when doing the same is not working. We are unable to remove the top arm pivot pin from his car to allow removal of the top arm and fitting the new cone.

This is what we have done...
The old cone was compressed so we were able to remove the old trumpet. The rubber cone is still trapped in the subframe tower but it is unloaded. Therefore, the top arm is unloaded.
We removed the rear nut on the top arm's pivot pin.
We removed the two 1/4" bolts holding the diamond plate securing the top arm pivot pin to the subframe.

That's when things fell down. The top arm will not move forward. After levering and prying for a while we gave up and removed the big nut from the diamond plate so we could verify if the pivot pin could spin in the needle bearings. It can. So the pin is free to rotate but we cannot move it forward to extract it. It won't move the tiniest bit. Again... the pin is free on both ends and it will spin in the arm but we cannot pull it forward and out of the subframe to free the top arm.

We removed the Zerk fitting on the top arm and sprayed penetrating oil into the arm (multiple times) only to see a flood of rusty, dirty penetrating oil come out. My gut feeling is that the pivot pin and needle bearings must be horribly rusty and/or the needle bearings have worn grooves into the pin preventing us from slipping it out.

Are there any suggestions for getting the pin out so we can free the arm? Are we going to be forced to cut the arm to extract it and then replace it and the pin with new? We have pushed, prodded, and pried every way we could think of. All advice is welcome.

If you've got the diamond plate off, can you get the front thrust washer off? Then you should have enough movement to cut the shaft front and rear and not damage the arm.

I was able to get the diamond plate off. Isn't the thrust washer between the subframe tower wall and arm? I can't get that out since the pin won't move forward.

I will check during my next visit to see if I can't cut through the thrust washer and shaft. My friend does not have an air compressor so I am going to have to see what I have for cut off wheels that will fit my disk grinder. Hopefully I have some thin reinforced wheels with the correct size arbor hole that will allow me to cut through both the thrust washer and pin.

assuming the problem is on both sides....
you may be able to obtain a clear enough path to the front of the car
(under the radiator on the LHS and past the clutch housing under any heater intake on the RHS) to make up a threaded connector using the large nuts holding the diamond plate to attach a cable or rod and slide hammer to wrench the pins out...with maybe some judicious oxy/acetylene heat on the arms?

the brake pipe unions to the front hoses and the brake switch I think will be in your way too.....oh and the radiator engine mount bracket.....

maybe the top arms might be replaced into the bargain too.

dklawson wrote:
My gut feeling is that the pivot pin and needle bearings must be horribly rusty and/or the needle bearings have worn grooves into the pin preventing us from slipping it out.

That is what I've found too with some like these (read below). I've nearly always been able to get them to move by levering between the body and the threaded end of the pin on the rear side, however, there was one once that like this wouldn't budge for love nor money. I ended up having to cut it through on the thrust washer on the rear facing end with a reciprocating saw. Ugle, but got the job done.

dklawson wrote:I was able to get the diamond plate off. Isn't the thrust washer between the subframe tower wall and arm?

The front facing thrust washer actually goes through the subframe and I'm also wondering since you say you can spin the pin itself if in fact this isn't frozen in to the subframe.

Spider confirms what I thought (without looking). The hole in the front tower wall is the size of the thrust washer, the plate then traps it in place.

If you clean up that area you should be able to pit the rearmost nut back on the pin and then drift the arm forward on the pin. If you can get it to move by a blade or disc thickness you should then be able to cut it out, hopefully on the narrower threaded parts.

Just thinking a little more from what Graham has suggested, if the front thrust is frozen, try belting the arm itself forward with a lump of hardwood a few times, now that the diamond plate has also been removed. That should help loosen it.

It’s a real bastard of a job when that pin has seized onto its bearings, that is for sure!

This is what I would do

Remove the little bump stop from under the top arm

Disconnect the top arm from the outer suspension hub

Refit the nuts and the little plate (so its back to how it was)

Take the grease nipple out and spray as much WD40 (or whatever you have) into the top arm

Using a drill, drill some holes in the alloy trumpet to weaken it, then smash the remains out the way using a hammer and a chisel (if you are replacing this with a hilo its not needed any more)


Once all this is done, you will be able to move the arm up and down, as the shaft has been tightened back up with the nuts, the arm will turn correctly on the bearings, keep working at it and spraying the WD40 into the arm to lubricate the bearings. Once the arm is able to move with no effort at all you have to assume that the bearings have given up their rusty grip on the shaft.

Then remove the nuts and try to withdraw the shaft, it should slide straight out.

BUT…..

If not, you have two options


1) Get an impulse puller / slide hammer and make an attachment to fit to the shaft by welding a nut to whatever the puller has on it, then you will be able to get a bit of hammer action on the shaft and it will just come out. Its awkward getting access through the front grill hole though and you won’t be able to get a ‘straight pull’

2) If its really seized on tight (which they can do if they have never been greased) your only option is to cut the top arm out with a disc cutter or a air saw – this is last resort obviously – when the bearing get really rusty they will just rust solid onto the arm and you just cannot get it out – if you didn’t want to do this , your other option would be to drop the frame out the car so you can get a good punch and hammer the shaft through the arm (I have also seen someone cut a hole in the floor to get access to do this, but that’s a real nasty way of doing it!!!)


You have to assume thought, that if the shaft is gripped onto the top arm, then the shaft and bearings will be damaged through rust, so its best to assume that you will need a top arm pin kit.

This is caused by lack of grease, so it’s a good idea to give the top arm greasers a shot every six months or so when you do the other ones!!


Hope this helps – it’s a nasty job to do, ive had it a few times!!!

These top arms are abundant and cheap to buy second hand in good condition, me I would get in with a grinder/ burning gear ( though that's smokey and dirty) and chop of the top arm off , the pin will be shagged anyway, you could spend all day trying to get the pin out and still not win
I think we should all put 50p together and buy Rich from minispares a grease gun for Xmas as he says he as done a few of these

[quote="goff"]These top arms are abundant and cheap to buy second hand in good condition, me I would get in with a grinder/ burning gear ( though that's smokey and dirty) and chop of the top arm off , the pin will be shagged anyway, you could spend all day trying to get the pin out and still not win
I think we should all put 50p together and buy Rich from minispares a grease gun for Xmas as he says he as had it a few times

These top arms are abundant and cheap to buy second hand in good condition, me I would get in with a grinder/ burning gear ( though that's smokey and dirty) and chop of the top arm off , the pin will be shagged anyway, you could spend all day trying to get the pin out and still not win
:lol
Goff

I wish the arms were abundant and cheap but Minis are not that common over here so we will do what we can to save the arm and sacrifice the pin.

I do have a couple of slide hammers. I can weld up a hook/bracket to use a chain or similar to attach it to the pin to try and remove it with force. Prying did not work, nor did fitting a large, heavy washer to the front of the pin and trying to drive it out with a "pickle fork" (as is sometimes used to split ball joints) placed between the subframe and washer.

I am confused by the statements about the front thrust washer. What I remember from years ago (and please do correct me if I am wrong) is that with the diamond plate unbolted and the large nut removed from the rear of the pin, the arm should just slide forward out of the subframe and top arm. The statements about the thrust washer fitting into/through the subframe confuse me in that I don't remember doing anything special to get the top arm out of my car several years ago.

Thanks for all the advice. I will discuss this with my friend and see how he wants to proceed. He is already building a parts order to buy a pair of the top arm rebuild kits.

EDIT: OK... never mind about explaining the front thrust washer. I Googled for pictures of the subframe after making the original post above. I now see the large diameter hole in the front of the subframe tower. The hole is clearly about the same size as the thrust bearing. I've got it now. Thanks.

photos here of the top arm and pin + a loose pin .Hope this helps with removal of the seized pin , In the early 70s i had a mini van that always squealed on the front suspension, i could not get any grease in , so ignored it until it snapped the pin on the front subframe side,then it was a second hand arm + pin ,always made sure i could get grease in after that.
Sorry i did not notice you were in the States.
Goff

Thanks for the pin assembly pictures. They really clarify what is supposed to happen.

Today I bought some 4.5" cut off wheels for my disk grinder and my friend has ordered his replacement pin/bearing kits. Now I just need to get back over there and get to work. Today is a holiday for us so I will try and get over there as soon as our schedules allow another work session.

goff wrote:These top arms are abundant and cheap to buy second hand in good condition, me I would get in with a grinder/ burning gear ( though that's smokey and dirty) and chop of the top arm off , the pin will be shagged anyway, you could spend all day trying to get the pin out and still not win
I think we should all put 50p together and buy Rich from minispares a grease gun for Xmas as he says he as done a few of these

Goff, top arms in good condition are starting to get a little thin on the ground in these parts, just like dlawson has found. Nearly every one you pick up has has the knuckle cup wear through and round out the bottom of those holes. We build them up with metal putty, and they are OK, but there's no substitute for good holes

Is it possible to put the diamond plate back on, loosely, with say,
1/4" between it and the subframe? Push some slightly longer 1/4"
bolts through the diamond, then through some 5/16" nuts used as
spacers, then through the sub-frame and finally put the 1/4" nuts on.

Put the 1/2" UNF nut on, but no washer and use it like a puller tool?
Molegrips on the tail end will probably be required to stop it spinning.

I am sure that I've used this method myself many years ago...

OK, it will only pull it about 1/4", but it might be enough to get it
past the problem spot. Repeat to fade...

If I am understanding the problem correctly, this could be easier
than the nuclear option!

Ian

We tried re-fitting the nut and a heavy washer on the pin after removing the diamond plate. We attempted to pry against that washer and we tried using a "pickle fork" between the subframe and washer to shock the pin out. Nothing worked. There is not really room for a puller in that location but we did consider trying a length of chain on the pin can using a slide hammer to pull on the chain.

Since my friend has ordered the arm rebuild kit we are just going to go straight for cutting the pin and sliding the arm out. I can take the removed arm to work and use a hydraulic press to remove the pin and needle bearings. If I clean it well enough I can grit blast it while I'm at work so it will be as good as new when we reinstall it.

doug

by the time you have hacked at the arm to get it into a situation where by it can be twisted to get it out the frame, the pin will be scrap.

its impossible (with a disc cutter) to get the access to do a neat job and not damage it

both times ive had to resort to this method, the arm has been in little hacked up bits by the time I was done.

Understood.

Obviously cutting the pin renders it scrap... which it would have been anyway. I remain optimistic regarding cutting the pin without damaging the arm. I certainly have to try. The cut off wheels I bought are 1/16" (1.5mm) thick and 4.5" (115mm) in diameter to "reach in". If it looks like that won't do the job I will switch to my reciprocating saw (Sawzall) with a metal cutting blade to cut the shaft.

the little 'hump' of the subframe where the rebound rubber sits gets in the way, so you cannot get a straight cutting angle to try and not damage the arm.

ive never tried with a saw blade, but suspect that the way the frame bends inwards behind the arm would mean that the blade would snag??

both times ive cut them out have taken an age to slowly chop the arm away to be able to get the cutting blade in - its a bit like chopping a tree down with an axe!