Suspension troubles.

So I received the new used a-arm today to replace the beat-up one that came with my car. The "new" ones a bit rusty but I have do media blast some parts so one more isn't gonna hurt. Any who After close examination and comparison to the "new" a arm and the other one that was on my car i found the cause for the destruction... Classic DPO screw up.. he didn't put on spacers.. so the fulcrum pin distorted its seats and eventually went halfway through the a-arm. So long story short, the pin is stuck inside the kingpin.. Any tips to get the bugger out? I wanted to get some work done on the a-arms so I could take a break from the 3 months of body work..

Adam

Lots of heat!.

Can you cut the pin so you can remove the a-arm (I know they are hardened)? Then you can put it on the bench, in a vice, heat it and drive the pin out.

Adam, I a little confused by your description of the problem. What spacers are you refering to? I'm not aware of any spacers between the fulcrum pin and the A frame. There are a couple of dust/grease shields but nothing else that I remember. The drawing from the VB catalog shows the pin (item 9) the dust shields (items 29 and 30). The pin goes through the kingpin assembly and is held in place and kept from rotating by the pin (item 28) which is a tapered pin and is held in place by a nut on the bottom. This pin is very soft, so it usually is a bear to remove as when you tap on it to drive it out it just swells and sticks, but a good drift should remove it. Then with a little penetrating oil the fulcrum pin should free up and slide out. The fulcrum pin is designed to rotate in the A arm bushings. Both the pin and the bushings are threaded, but they should rotate slighty in use which causes the wear when they aren't kept well lubricated. You may have to cut the pin on each side of the kingpin with a hacksaw and then drive out the center area from the kingpin if you can't get it to free up once the keeper pin is removed and you've tried some penetrating oil.

Adam,

Bills advise is as always very accurate. I think the problem you having is with the retaining pin (see item 28 on Bill's diagram). This pin is tapered and must be driven out from the threaded end with the small nut either removed or in most cases broken off when you try to loosen it. The pin locks the king pin to the fulcrum pin.
The retaining pin (#28) is not reusable. If you use some penetrating oil on the fulcrum pins and move the kingpin back an forth before you remove the the retaining pin, you will have an easier time when you unscrew the fulcrum from the A arm.

Good Luck
Dave

After U do it once, you'll be an expert. The first time is a B---h!

I have to say that I have never seen a good used a-frame. The threaded bushings are almost always worn, otherwise they'd still be on the car. Get new,or get rebuilt. The bushings are what get replaced.

PeterC

Peter, I was not aware of a Rebuilt a-arm.. in fact I didn't think there was anything rebuild able on it. Bill you hit the nail on the head. I assumed that the dust shields were spacers and the lack of them played a role in the damage to the old a-arm. For item 28 it wouldn't budge with a drift so I ended up drilling it and then drifting it. The fulcrum pin is still stuck in the kingpin. I soaked the pin in oil last night so maybe a nights worth of soaking my yield some results. Thank you all for your replies! I'm sorry for the confusing first post.

Adam

Adam, no need for apologies, we've all been in your shoes before. In my almost 50 years of working on cars, both old and new I've never seen anything but the Morris group use anything like that fulcrum pin system. Most are like the system used on the MG T series up through the MGB and use a bushing in the lower trunion.
As far as the rebuilt A arms go, the wear in the threaded bushings requires them to be replaced. They are brazed in place and it takes a special fixture to maintain the exact alignment both in bore center and also in thread position so the fulcrum pin will thread in correctly. I've toyed with the idea of replacing this with a smooth pin and some urethane bushings, but the d**n things are pretty reliable if kept lubricated so I haven't had to replace mine yet. If I do I think I'll look into the urethane solution.

Bill, the "problem" is that the threaded bushings actually provide more surface area and positive location than the alternative would in the same 1 piece arm configuration. The design isn't at fault, except for lack of a zerk at the blind end, and, naturally, lack of previous owner's diligence in greasing. I was a DPO with my first. I apologize to whoever got it ;-)

Peter C.

You're right Peter, the lack of a grease fitting in the blind end does cause a lot of problems. Even if you grease the unit regurally you usually wind up pushing the grease out the seal on the big end before it actually goes up into the blind end and gets on the threads. I hadn't thought about the surface area before, but with modern materials such as urethane or MDS filled Nylon as a bearing material I think I might be able to build something that would last at least as long and be easier to replace. Once the threaded bushings start to wear you're sunk, if a nylon or urethane bushing started to wear then you'd have a loose joint, but you could insert a new bushing without having to rebuild the A frame. Of course that's just me, trying to build a better mouse trap even if there aren't any mice around.