Dropping the IRS
#1 Dropping the IRS
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.
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.
Best Regards
Philip
Jag: 72 S3 XKE, 74 S3 XKE OTS, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)
Philip
Jag: 72 S3 XKE, 74 S3 XKE OTS, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)
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christopher storey
- Posts: 5698
- Joined: Sun Mar 09, 2008 3:07 pm
- Location: cheshire , england

#2 Re: Dropping the IRS
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
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#3 Re: Dropping the IRS
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,
Regards,
Regards,
Simon
Series III FHC
Simon
Series III FHC
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#4 Re: Dropping the IRS
Just curious, how many hours did it take to remove the unit?
Steve
Steve
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#5 Re: Dropping the IRS
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.
I should add that I have a large workshop trolley jack which did make lowering and raising the IRS really easy.
Best Regards
Philip
Jag: 72 S3 XKE, 74 S3 XKE OTS, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)
Philip
Jag: 72 S3 XKE, 74 S3 XKE OTS, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)
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#6 Re: Dropping the IRS
Philip, thanks. Much shorter than what I had anticipated from reading other posts. Its an early next year project for me.
Steve
Steve
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#7 Re: Dropping the IRS
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
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc
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#8 Re: Dropping the IRS
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.
Best Regards
Philip
Jag: 72 S3 XKE, 74 S3 XKE OTS, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)
Philip
Jag: 72 S3 XKE, 74 S3 XKE OTS, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)
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#9 Re: Dropping the IRS
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

Steve

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#10 Re: Dropping the IRS
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
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc
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#11 Re: Dropping the IRS
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
Steve
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#12 Re: Dropping the IRS
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,
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,
Regards,
Simon
Series III FHC
Simon
Series III FHC
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