Home made polybush press

[Bainbridge]

Hi all, I've a full polybush replacement job coming up, an in addition to my threaded rods and pullers I was thinking of making this frame out of thick angle iron to use with a trolley jack to persuade some of the big poly bushes with lips on home:



Needless to say I'll be standing well back wearing PPE.

Even if I just get it greased up and under pressure overnight this might do the job.

Any thoughts?

I know I can get a press for £100 odd, but my garage is already full to bursting and I took on this job to keep the cost down, so am looking at as many DIY tips and tricks as possible.

Thanks

[andburg]

take the cylinder out of the frame so its just a ram in a frame? my concern would be making sure its all lined up for a straight push.

cylinder out, mount it into a frame? the frame could them be mounted horizontally into a large vise

[Bainbridge]

That's a good idea, I didn't think of that.

Also, if I did mount the frame around the jack, the pressure point would move back as the jack rises, whereas the cylinder just goes up and down.

Hmm.

They're polybushes and do have a bit of give. Maybe if I could get the insertion started, then take off the pressure and readjust, and repeat until done.

The threaded rods and pullers might do it anyway, and I don't need to press the old rubber bushes out, I'll be cutting them out and removing the steel shells.

Thanks for your input.

[GreenV8S]

I expect a simple puller will be all you need.

If you do try the trolley jack approach, note that the bush/sleeve stacked on top of the trolley jack as you've shown will be unstable since the frame would be free to pivot at the point of contact with the trolley jack. You could address that by putting a wide enough base on the frame, but I'm sure you'll find you don't need any of this.

[Bainbridge]

Yes it will wobble about a bit but I'm hoping, if I need to use this method, that once a bit of pressure is on it, it might hold.

I've also got some fine pitch threaded rod, my thinking being that it will enable a more gradual increase in pressure than a coarse thread.

Fingers crossed they will go in fairly easily, it's just the big one piece bushes with lips for the front control arms that I think might need some force.

[GreenV8S]

Bainbridge said:

I think might need some force.

A threaded 12mm steel rod is probably good for a couple of tons, which is in the same ballpark as a typical trolley jack. A high tensile acme thread would carry far more, but that's getting a bit specialised. If you find it's stripping the threads, use a coupling nut.

[Bainbridge]

GreenV8S said:

A threaded 12mm steel rod is probably good for a couple of tons, which is in the same ballpark as a typical trolley jack. A high tensile acme thread would carry far more, but that's getting a bit specialised. If you find it's stripping the threads, use a coupling nut.

Thanks for this info. The old spare jack that I was going to use was 1.25 tons, so if the threaded rod is good for at least that amount there's no benefit from me trying to use the jack as a press.

Great idea re coupling nut. I've seen those 'long nuts' about, but didn't know their name.

I'll buy a few in readiness to hopefully start work on the weekend.