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#1 Dropping the IRS

Posted: Fri Jun 02, 2017 6:23 pm
by jagwit
Yesterday, I had the opportunity to drop the Independant Rear Suspension (IRS) from a friend's E-type for the first time. I really did not look forward to it but it turned out to be easier than pulling the engine/tranny combo.

I simply suspended the car high on two trestles with a substantial U-shaped iron bar and supported the IRS on my rather substantial trolley jack, loosened everything, and dropped it.

Lesson learnt:
1) loosen then IRS mountings from the IR, NOT from the body. It is very difficult to get the nuts back onto the the mountings with the IRS in place;
2) disconnect the handbrake cable when the IRS has dropped about 4" (100cm);
3) replace the IRS mounts by fitting them to the car, not the IRS.
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#2 Re: Dropping the IRS

Posted: Sat Jun 03, 2017 8:00 am
by christopher storey
I think you will find it is easiest to replace the IRS by attaching one set of the mounts to the body , and one to the IRS. It is some while since I have done it, so I can't remember whether front or rear is best , but if you search the threads you will find the answer

#3 Re: Dropping the IRS

Posted: Sat Jun 03, 2017 8:37 am
by vee12eman
I bow to others experience, but I definitely agree with Philip. I always attach the mounts to the car first, but I guess it is personal preference.

Regards,

#4 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 2:54 am
by SRK
Just curious, how many hours did it take to remove the unit?

Steve

#5 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 5:00 am
by jagwit
At most two hours, including lifting the car and supporting it some way to work on the IRS.

I should add that I have a large workshop trolley jack which did make lowering and raising the IRS really easy.

#6 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 1:53 pm
by SRK
Philip, thanks. Much shorter than what I had anticipated from reading other posts. Its an early next year project for me.

Steve

#7 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 2:42 pm
by mgcjag
Hi Steve...as mentioned if you know what you are doing and have a good plan then it dosent take long.....its a very heavy unit and is too much for two people to lift......if you have access to a lift then once the prop, brakes are disconnected lower the lift so tbe irs sits on something.....undo the mount bolts then raise the lift leaving irs below...without a lift you have the rear end jacked up and the irs balancing on a jack that you have to lower down.....just work out a plan of how to do it and once its down how to move it...i used an engine crane to move it around the workshop.. Steve

#8 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 2:54 pm
by jagwit
Its pretty much impossible to disconnect the handbrake cable with the IRS in the car. Once its lowered about 6" (15cm) it is much easier to disconnect the handbrake cable.

#9 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 3:27 pm
by SRK
Thanks for all of the tips. I have a great shop with all of the equipment. I will have to figure out how to do this with the 4 poster (i'm thinking I support the car as Philip did but off the lift runners and then lower the IRS on my jack with some thick plywood underneath it so I can roll it out) But as you all suggest, I will put together a plan to make sure its safe and efficient. My IRS does need a full rebuild. Bushings have lots of miles and there's diff oil weeping all over the place.

Steve

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#10 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 4:18 pm
by mgcjag
Hi Steve....with your set up there it will be even easier.....just drive 3/4 the way onto the 4 poster remove the drive on ramps and support from the crossbeam to the car underside....raise the lift to waist height and put a support/ workbench under the irs....disconnect the mounts then raise the lift up leaving irs on bench

#11 Re: Dropping the IRS

Posted: Sun Jun 18, 2017 11:15 pm
by SRK
Nice, cantilevering the rear end off the lift will sure make it easier!!! I have a number of wood dollies so I'll just build a quick frame to put on top of two of them. Thanks for the tip!!

Steve

#12 Re: Dropping the IRS

Posted: Mon Jun 19, 2017 1:01 am
by vee12eman
Hi,

I agree that two hours or so is realistic if all the bolts release and parts separate easily. The problems are normally associated with the radius arm forward mountings, which tend to have corroded together. I suggest you try to release these prior to commencing the journey to identity if you will have problems. At very least, start to soak them with penetrating fluid. Otherwise allow time for the fact you might need to cut the rubber then release the metal cup later-obviously destroying the mount in the process.

If the car is a Long wheel base (2+2 or Any Series 3), there is a trick which helps by enabling you to use jack screws from above. I don't think that this is possible with any SWB cars.

Regards,