Fitting A Celica Diff To Your Ke70

[altezzaclub]

After the multiple runs up to Queensland over the last year, the diff in The Girl's KE70 is noticeably whining, particularly at 100kph when coasting. I figure it could be outer axle bearings, or diff bearings, or wear in the crownwheel and pinion, all of which are nasty jobs!

 

So I spent $100 to drag an RA60 diff out at the wreckers, figuring it might be in better condition, but certainly it will give a better cruise as its 3.9 instead of my curent 4.3, and its a banjo style rather than the BorgWarner Salisbury style which means there are LSDs for them!

 

Having spent all yesterday afternoon under a Celica in the mud, I spent all today under a KE70 in the shed, and seeing I have found what is needed I will spend all tomorrow swapping the Borgwarner back in... I hate cars!

 

Here's the story-

 

The RA60 VIN plate listed a T312, so a 3.9ratio with no LSD. It was an auto, as was our KE70 originally.

 

Side by side, the RA60 is 15mm wider overall, axle face to axle face, something you can't see when it is fitted. The brake shoes are 40mm wide, while the KE70's are 35mm. Naturally the slave cylinders are larger too,

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

as are the drums. The RA60 runs an inch bigger in diameter.

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

The top arm mounts on the RA60 are shorter diagoally, so the arm bolts on lower and pulls the diff forward. The RA60 arms are the same lengths as the KE70, except the Panhard rod.

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

The RA60 has an extra inch between the left and right mounts across the car, so it splays the arms 12mm each side. The lower mounts are the same distance apart, but the RA60 bolthole is about 10mm lower than the KE70.

 

The arm bush width is the same, so an arm fits into either type of mount. However the RA60 uses 14mm bolts, the KE70 uses 12mm, so using the KE70 arms and bolts means they are sloppy in the RA60 mount holes.

 

To use the RA60 arms means drilling the KE70 chassis mounts out to 14mm, or sleeve the RA60 bushes down to fit the 12mm bolts at the chassis end.

 

To use the KE70 arms and bolts I could weld 12mm washers onto the RA60 mounts, or maybe press an RA60 bush into the back end of the KE70 arms.

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

The RA60 spring has a bottom diameter 10mm less than the KE70, so the springmount on the Celica diff does not locate a KE70 spring very well. I'll try a couple of Celica springs for rate and see which is best.

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

The biggest problem is in the pinion flange. The RA60 flange is 10mm longer towards the gearbox, so the KE70 driveshaft pushes in beside it with some difficulty. The KE70 driveshaft goes up with about 5mm of gap, so you can see that it is a tight fit. That will destroy the back of the gearbox over a bump I reckon.

 

The holes in the RA60 are on the corners of a rectangle that is different in size to the KE70.. You can put in two bolts OK. Worst of all, the locating shoulder on the KE70 driveshaft is about 12mm bigger in diameter than the depression in the RA60 flange, so it does not fit in there.

Edited April 4, 2013 by altezzaclub

[B.L.Z.BUB]

I'm liking where this is headed.

[GJM85]

Ke55 are 229mm.... This causes rear bias when braking.

[altezzaclub]

Surprisngly enough, for all the differences in the mounts, the diff sits at quite a natural angle when fitted.

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

he RA60 panhard rod is 50mm shorter than the KE70, but even that is not enough to make the KE70 one fit. It is still 45mm too short to reach the RA60 mount.

 

So, a test drive was undertaken with two bolts holding the driveshaft onto an unlocated diff nose, no panhard rod and the bolts sloppy in the mount holes! It was enough to carefully get it up to 90kph and find it is quieter than the Borgy, the brakes work fine, and so tomorrow it comes out while I solve these problems.

 

Driveshaft- I'll try a Celica shaft or graft the rear UJ & flange onto the shortened KE70 driveshaft.

Panhard rod- I'll get the Celica one sleeved 95mm and keep the KE70 stock.

Springs- Celica rears, RA40 or RA60 or whatever I can find.

Bolthole diameter... I shall think about...

Edited April 3, 2013 by B.L.Z.BUB

[B.L.Z.BUB]

You know how in seat belts there is a washer/spacer that has the stepped in part so the seat belt can rotate?

Something similar for the bolt holes?

 

Hang on I think I have this backwards...

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

This causes rear bias when braking.

 

yeah I'm hoping!

[altezzaclub]

You know how in seat belts there is a washer/spacer that has the stepped in part so the seat belt can rotate?

Something similar for the bolt holes?

 

Would be ideal! But its only 1mm radius so its a very thin spacer...

[B.L.Z.BUB]

Yeah was just thinking that. Must be able to mix and match bushes to suit surely?

Even if you could just punch out the steel sleeve, drill it out to 14mm and insert the RA60 sleeve?

Edited April 3, 2013 by B.L.Z.BUB

[altezzaclub]

OK, swapped them back today, and editied the post to reflect that the KE70 driveshaft has its holes in a rectangle too, just a different size.

 

They both weigh within a Kg of 29kg at one end, so 60kg odd each. I borrowed the new neighbour's glass-topped bathroom scales so didn't want to dump a whole diff on them! The RA60 diff casing is probably notceably lighter as it contains bigger brake components and bigger crownwheel & pinion.

 

Sway bar washers might be the go for the bolt size difference, they are only about 1.5mm thick and have a locating flange punched out of them.