Suspension Question - Lowering and replacing 1 ton shackles

[shaunmax]

I'm currently restoring a Series 3 GS (and converting it to a station wagon configuration) and want to reduce the height a bit more in line with the height of a civvy spec vehicle. So when I refurbed the rear I replaced the extended 109" 1 ton type shackles and replaced them with normal shorter ones - and I set the front of the rear springs in the top hole in the chassis hangar, as my logic said that if I had shorter shackles I needed to use the top hole in the chassis hanger - although not sure that this is right now ........

I've spent today trying to rebuild the front suspension with the same logic ( shorter shackles and top hole in the front chassis hangar) but try as I might I couldn't push the spring to the top hole so i admitted defeat and had to make do leaving them located on the lowest hole. Seems though that this is correct when you look at 60.20.01 in the workshop manual...

So my first question is: Is the way I have mounted the front springs correct (lower hole in front hangar as per manual - with the shorter shackles) and 2. does this mean I should relocate the rear springs into the lowest hole in the chassis hanger.

Hope this makes sense - I'm more concerned the geometry will be adversely affected (although looking at it, my gut tells me it won't make much difference) but it would be very much appreciated to have some educated feedback on it.

Thanks in advance

[JDNSW]

No, what you have done with the front is not correct. The front of the spring needs to be in the upper hole if the shorter shackles are fitted, and this matters at the front, as it changes the castor angle on the swivels. (It does not matter much at the back axle)

Why can't you get the spring into this position? Likely reasons are a build up of paint, or repairs that have left welds that need to be removed.

John

[clubagreenie]

Problem at the rear is it may induce vibration by changing the pinion angle

[shaunmax]

No, what you have done with the front is not correct. The front of the spring needs to be in the upper hole if the shorter shackles are fitted, and this matters at the front, as it changes the castor angle on the swivels. (It does not matter much at the back axle)

Why can't you get the spring into this position? Likely reasons are a build up of paint, or repairs that have left welds that need to be removed.

John

John thanks for this, what is contradictory/ confusing is that the workshop manual seems to shows the lower hole used along with the shorter shackle dimension. Which is what made me second guess what I had done ....

In terms of why I couldn't get the spring to go into the top hole, I think it's just too tight - so a tolerance issue rather than anything else. I'm using poly bushes from 4wd in Victoria - I should check the length against a conventional bush - the rears were very tight too if I recall.

[clubagreenie]

Given it's ex mil it will have longer shackle plates and extended chassis plates. We made both of these by the dozen (access to gas profile cutter) and it's a simple process to lift without needing to change springs. You can slot the springs back into the upper holes but you'll also need the shorter shackle plates other wise you have the aforementioned castor issues.

In the manual I don't believe it would show the service spec suspension. I don't know if it was fitted factory to order for contract or done as an in service mod before they were released for use.

[JDNSW]

Given it's ex mil it will have longer shackle plates and extended chassis plates. We made both of these by the dozen (access to gas profile cutter) and it's a simple process to lift without needing to change springs. You can slot the springs back into the upper holes but you'll also need the shorter shackle plates other wise you have the aforementioned castor issues.

In the manual I don't believe it would show the service spec suspension. I don't know if it was fitted factory to order for contract or done as an in service mod before they were released for use.

Reread the original post. He has already replaced the longer 'One Ton' shackles with standard ones, and needs to move the front of the spring to the upper hole.

John

[JDNSW]

John thanks for this, what is contradictory/ confusing is that the workshop manual seems to shows the lower hole used along with the shorter shackle dimension. Which is what made me second guess what I had done ....

In terms of why I couldn't get the spring to go into the top hole, I think it's just too tight - so a tolerance issue rather than anything else. I'm using poly bushes from 4wd in Victoria - I should check the length against a conventional bush - the rears were very tight too if I recall.

Try spreading it by putting a section of threaded rod through the lower holes with two nuts between the cheeks, and winding them apart.

I hope you don't have the axle U-bolted on to the spring - that just makes life more difficult, as, if you think about it, unless both side springs are at exactly the same height, they will be twisted by the axle. It is a lot easier to seat the axle once both springs have both shackle pins in place (but not tight).

John

[shaunmax]

Try spreading it by putting a section of threaded rod through the lower holes with two nuts between the cheeks, and winding them apart.

I hope you don't have the axle U-bolted on to the spring - that just makes life more difficult, as, if you think about it, unless both side springs are at exactly the same height, they will be twisted by the axle. It is a lot easier to seat the axle once both springs have both shackle pins in place (but not tight).

John
John thanks - I had tried the threaded rod idea on one side but there didn't appear to be enough clearance past the nuts to get the spring in but I think I'll have another go at the weekend.... So thanks for that

And will definitely have a go without the axle ( which I think was just making life way too hard!)