I understand how the rear toe angle is supposed to be adjusted using shims between the rear subframe and the trailing arm brackets but the fitting to the body of the subframe mount mystifies me...
... Why is the bolt hole in the floor oversized? Presumably so that if a mount has to be changed one doesn't have to struggle vainly getting everything to line up.
However, does it mean that if a subframe mount is changed, even if the body of the car and also the subframe are supported, that the rear toe-in needs to be remeasured and probably adjusted?
Rear toe angles
- david_lall
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Last edited by david_lall on Fri Jan 01, 2021 6:02 pm, edited 1 time in total.
David Lall
1972 Triumph 2.5 PI Estate Royal Blue
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1995 Lada Riva 1.5 Estate Cherry
1972 Triumph 2.5 PI Estate Royal Blue
1968 MG 1300 Saloon Connaught Green
1978 Carlight Casetta Caravan
http://carlightrestoration.blogspot.co.uk
1995 Lada Riva 1.5 Estate Cherry
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Re: Rear toe angles
The shims behind the trailing arm brackets adjust the toe-in between the wheels, and nothing apart from damage will alter that once set.
The two sub-frame arms are locked together at the diff nose piece, so the two wheels on the trailing arms form an independent unit.
This unit is attached to the car at the rear of the diff, and also at the ends of the two arms through the large holes you describe.
So it is theoretically possible for the toe in to be correct but the entire unit misaligned with respect to the body and the front wheels, because of the oversize mounting holes.
I don't know how one is meant to ensure that the alignment is correct - in practice there is not a lot of choice because the position the whole assembly adopts will be determined by the interaction of the 4 mounting points.
My practice has been to set the toe-in correctly, and then check that the assembly is aligned by sighting along the edges of the front and rear tyres and confirming by eye that the offset is the same front and rear.
That's always seemed good enough, but I suppose a full laser optical alignment would do the job properly.
The two sub-frame arms are locked together at the diff nose piece, so the two wheels on the trailing arms form an independent unit.
This unit is attached to the car at the rear of the diff, and also at the ends of the two arms through the large holes you describe.
So it is theoretically possible for the toe in to be correct but the entire unit misaligned with respect to the body and the front wheels, because of the oversize mounting holes.
I don't know how one is meant to ensure that the alignment is correct - in practice there is not a lot of choice because the position the whole assembly adopts will be determined by the interaction of the 4 mounting points.
My practice has been to set the toe-in correctly, and then check that the assembly is aligned by sighting along the edges of the front and rear tyres and confirming by eye that the offset is the same front and rear.
That's always seemed good enough, but I suppose a full laser optical alignment would do the job properly.
Re: Rear toe angles
I usually change a rear subframe mount one at at time, which reduces any possible movement of the whole unit, especially if the opposite wheel is kept on the ground. I fortunately have a pit, so the car doesn't have to be raised as much for access, and the vertical movement on each side of the subframe is minimal, as the mountings are fitted from the bottom. If you are refitting the original anti vibration straps, that is a good indication of their original fitted position. Usually, there are also marks left in any underseal or paintwork on the body above the mounting, and in the grey body sealant under the seat base, that give a good indication and guide to their original fitted position.
Register Member no. 1596
1967 Mk1 2000 in Gunmetal Grey
1969 Mk1 2000 in Royal Blue
1970 Mk2 2000 in Valencia Blue
1972 Mk2 2.5 PI in Triumph White
1973 Mk2 2.5 PI in Sienna Brown
1976 Mk2 2500S in Carmine Red
1967 Mk1 2000 in Gunmetal Grey
1969 Mk1 2000 in Royal Blue
1970 Mk2 2000 in Valencia Blue
1972 Mk2 2.5 PI in Triumph White
1973 Mk2 2.5 PI in Sienna Brown
1976 Mk2 2500S in Carmine Red
Re: Rear toe angles
Hello all,
The oversize mount hole is something I decided to correct. I turned up a spacer to fit accurately in the floor with a central hole to suit the attachment bolt.
That done I then set the toe in.
Alec
The oversize mount hole is something I decided to correct. I turned up a spacer to fit accurately in the floor with a central hole to suit the attachment bolt.
That done I then set the toe in.
Alec
0465
MK1.5 2.5 P.I.
Jaguar MK 2 (Long term restoration.)
Hymer 564 Motorhome.
MK1.5 2.5 P.I.
Jaguar MK 2 (Long term restoration.)
Hymer 564 Motorhome.
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