[Guide] "How to fit RT142 rear disc's to most 4 studs"

[GA61XX]

How to fit RT142 rear disc's to most, Toyota 4 stud rears..

This thread is for the use of the 1985 RT142 rear disc's.. (some times found on the ST141, even thou i've never seen it.) (Note :- the 1986 RT142 has IRS & do Not fit.)

You will need :-
4 stud diff' eg. RA23/8, RA40/60, TE72, or MX13/23.. there may be others.
1 x set 1985 RT142's rear brakes, all inc'
2 x retaining plate spacer rings (you can use the RT142's plates & rings, But ring's will need to be removed & welded to the MX13/23's retainer plate)
8 x Hi-Tensile bolts, 45mm long x 10mm metric fine (1.25mm) . With one side linished to fit the axle.
(use stock nuts.. with loctite 262. )
1 x set shocker hanger's.. (used on TA22/3, RA23/8, MX13/23, & TE72)
2 x axle bearing spacer rings.. (used only with MX13/23 diff' )
1 x set RT142's steel brake lines.. (These can be used on the RA40/60 & MX13/23 diff's)
1 x new set of steel brake lines. RA23/8.. Note : (old ones may be used, if in good condition, But you will still need them shortened.)

New parts list.
2 x set of axle bearings.. part number (CBC) :- TJ215B kit (MX13/23, RA23/8, RA40, RA60, TE72 & others)..
1 x set. Rear pad's # DB 1098
2 x Rear rotors # PBR 706
2 x Seal Kit # K1610s
Rear shoe's # Reshoe only
Note:- when ordering the rotors, you may have to ask for ST141 rear disc's..

Other mod's needed
Q:- what are you fitting them to ..??
(1) A:- RA40/60 needs 2 x 5mm holes drilled & tapped 6mm... (used to hold rubber hose bracket to diff' )
(2) A:- RA23/8, & TE72 needs the shocker mount to be moved, & 2 x 5mm holes drilled & tapped 6mm... ( welding also involved ) = (engineering)
(3) A:- MX13/23, needs the shocker mount to be moved also, & 4 x 5mm holes drilled & tapped 6mm... ( welding also involved ) = (engineering)

Here are a few sets of the Rear Disc parts...



2 x retaining plate spacer rings, & 8 x Hi-Tensile bolts.



Some people seam to cut the ring on one side & slipped over the axle. They do this, so when they brake an axle, its easy to change over..
As an engineer i don't recommend the cutting of the ring accept for "off road/race" vehicle's.. as there is a chance that it may become loose & get caught in the wheel bearing & cause the wheel to jam/fall off....




It is best to fit new bearings & have the ring welded to the retaining plate..



How to weld ring in place..

Place the 4 x bolts in the holes, with the points to the middle, to hold the ring in the centre. (as seen in the pic' above.)
Then clamp & 2 x small welds. (Note :- these welds are only small,& if higher than the ring will need to be filed down level with the top of the ring.)
This is then slipped on to the axle, with the axle bearing then pressed on & shrink ring then added.

Hand Brake Cable's..

The RT142's rear Disc's & hand brake cables are the go on all early Celica's.. But..
For a TA22/3 or RA23/8 & TE72's you need 2 x Right hand side cables..
Also some early RA40 need 2 x RH cables..
But other than that RA40/60, & RT141/2's, have one longer one.. the left.. Note :- ( cable is same length, it's the outter that is longer, & you would have to move the mount on the chassis..

When fitting the cables to a TA22/3 or RA23/8, you will need to remove the tail shaft, so as to put a small bend in the holder for the plastic bush, after small bend to open it a bit, use a round file to file the hole round again to form a "C" .. now fit cables.. & tail shaft..
The plastic bush on the RA40/60 & RT142 are the same size, But the early cars, eg. TA22 & RA23/8 had smaller nylon bushes.. TE72 may also have smaller nylon bushes...??

..

[GA61XX]

TA22/3 & RA23/8 Diff's

You will need to move the shocker hangers, on the TA22/3 & RA23/8's diff' as the shocker will foul, on the caliper if you don't move it..

You will need a set of donor hangers.. get these from the same car you get the disc set up..
This is how they look when i get them from my local wreckers, with min' cuts with a hack saw.. then i clean them up with the grinder, when i get them home..



these need to be cleaned up thus..



Now the old shocker mount needs to be removed from the diff..
You will need a angle grinder..
Note :- when doing this, you must not damage the lower control arm hanger..



You now have to weld the new shocker mount..
You will need a welder & clamps..



White line & top of mount is 5mm down, & a 3mm spacer to side of the hanger..





Centre of shocker mount is 95mm from the diff face, i used a pice of angle clamped on..



Hole is needed to be drilled & taped 6mm.. ( i'll get a mesurement next time i do one ) but pic's should help for now..

R/H side..



L/H side..

[GA61XX]

Mounting braket on the end of brake line rubber hose needs to be cut & drilled with a 7mm hole, & small bend..



Cut on white line, drill hole & bend on dotted line ( about a 5deg' bend.)

[GA61XX]

RA23/8 "T" Diff' finished..

Note:- The 2 x R/H hand brake cable's..



Note:- the bolt is only linished just enough, to clear the diff' end bearing cap.
This is so the bolt dosn't spin when doing up the nut's..



Here is a few pic's of the sway bar mount..

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PM Questions at the moment as i is still writing..

[GA61XX]

RA40/60 "T" diff'


With fitting the RT142's disc's to the RA40/60 you can also use the steal brake lines from the RT142, these will be a good fit... & as they are a factory part you will not need to get an engineers report on them.. well only to state that they are from a RT142, & therefore are covered by the engineering done by Toyota..

To fit the rear disc's to a RA40/60's diff housing, you will need to drill, 2 x holes & tap with a 6mm.. this is to hold the rubber hose to steel line bracket..

You will need :-
5mm drill bit
6mm tap

the 2nd hole needs to be 20mm from the centre of factory hole..
centre punch & drill with 5mm, then use the 6mm tap.. see pic's below..











Note:- With this done you can use the factory RT142's steel brake lines..


As the RA40's didn't have a rear sway bar, i would use a RA60's diff' house, as it has the hangers for the rear sway bar.. All the center & axles will fit from the RA40's diff' to the RA60's housing, (Note :- The RA60 has one stud that is longer, this can be swopped with one from the RA40's housing.) once you've fitted the RA60's diff to the RA40 you can use the chassis hangers from the RA60 & then get an Engineer to weld them to the chassis of your RA40 in the same place they was in on a RA60... (i'll try to get some more details of this)

(Remember this should be done by an engineer)

PM Questions at the moment as i is still writing..

[GA61XX]

RA40/60 "F" diff' conversion using MX13/23 diff'

With the MX13/23 "F" diff' the disc's will not sit in the centre of the caliper, & a New axle bearing spacer ring is needed, to offset the axle... to bring disc to the centre of the caliper...

By having the Factory Spacer replaced by the New Spacer it will be captive & not move..
the Toyota factory did all of the engineering for the use of a spacer in this position for the Drum Brakes.. so if we use a spacer ring with the correct sizes needed to off set the RT142 Disc's, it will still be with in the factories engineering..


watch this space for more info..



factory bearing, & bearing spacer ring..


New bearing retairer ring, welded to retainer plate


New bearing retairer ring, welded to retainer plate & axle bearing spacer ring on axle.


& with bearing & shrink ring...


New axle bearing spacer ring's


more pic's &...


PM Questions at the moment as i is still writing..
But any way how dose it look so far..??

[GA61XX]

MX13/23 "F" Diff'

same as with the MX13/23 to RA40/60 you will also need to use the Bearing spacer ring when using these "F" diff's...
Please, see in the above .....................

Also with the MX13/23 diff's you will need to use the MX13/23's Retainer plates, as the RT142's do not give enough clearance to the Bearing & spacer...
the Retainer Ring is the same as the RT142's & therefore the same as the ring used in the other conversion, so it can be copied by a machine shop, or you could removed from the RT's retainer plate & weld to the MX13/23's retainer Plate..


As for the MX13/23, section of this thread it's not started yet.. But you may need to also move the hanger on these diff's as well ..???
(i think i should of done a dry run on this before i did the last RA40/60 diff'.. any way i'll try to track down another MX13/23 to finish this section of thread..)


Below is the Ring set/kit needed for MX13/23 "F" diff' with RT142 rear disc's...





for those people wanting the Details of these rings Please send a PM, & i'll gladly send the details of them to you..

Note :- i've been asked as to why we need to use a new spacer ring on these axles... & here it is..
Well as Toyota used the same axles in a few different cars/diff's with different brakes fitted to them. & the spacer ring was used to shift the axle to accommodate the these different set up's.. Hence this is why it is best for us to do as what Toyota did.. & they have covered all the engineering for it..
By doing the same we will save many $'s with our engineers & the reports needed...


Odd diff's & details here..

Just holding this space for future blog..

[Hen]

Just adding my 2c after doing this to a T18 T series diff in my Sprinter.

I moved the shock mounts so the thick bar to which they are mounted sits vertically, about in the centre of the lower trailing arm mount (basically it looks further inboard than shown in the photos above). My shocks still run fairly close to the calipers. So check the caliper position before you weld.

I used Corona bearing retainer plates, with the ring already welded on. Centreing it with the bolts is a good idea though. I never thought of that one.

I used of of the 8mm headed bolts attaching the stone shield to hold the mount for the end of the rubber hose. This also meant I could use the stock hard lines on the diff.

Hen

[DoctorDubb]

Now this is probably a really stupid question... but why dont you flip the caliper/intergral drum backing plate from the left side to right side and right side to left side??

The bolt holes would line up still (if my rotations in my head work lol), the calipers would be sitting at the 'car front side' of the disc rather then the back. I dont think this would be a problem as i have seen many other cars e.g. lancers im pretty sure, run calipers on the forward side of the disc. This one maybe the brake gurus can answer?

The brake lines look like they cold be in the same position as the flexible bit *looks* to be long enough to reach the forward side. The handbrake cables would be coming out the rear but a quick bend would have them to the front again - *possibly* a bit shorter?

This way you should be able to not have to move the shock mount...

Problem though is that maybe it hits the lower trailing arm or spring perch?

EDIT: p.s. Ga61 i must spread rep around before giving it to you again

[GA61XX]

Now this is probably a really stupid question... but why dont you flip the caliper/intergral drum backing plate from the left side to right side and right side to left side??

The bolt holes would line up still (if my rotations in my head work lol), the calipers would be sitting at the 'car front side' of the disc rather then the back. I dont think this would be a problem as i have seen many other cars e.g. lancers im pretty sure, run calipers on the forward side of the disc. This one maybe the brake gurus can answer?

The brake lines look like they cold be in the same position as the flexible bit *looks* to be long enough to reach the forward side. The handbrake cables would be coming out the rear but a quick bend would have them to the front again - *possibly* a bit shorter?

This way you should be able to not have to move the shock mount...

Problem though is that maybe it hits the lower trailing arm or spring perch?

Just move the shocker mount....
The RT142 calipers are good as is.. so why swop....?? anyway handbrake cables would point to the rear of the car.. so why swop....??

Shocker mount is easy to move....
The amount it is moved is within the engineering spec's ....
As an Engineer i've done my home work on this mod' & all is good....
I've had many of these pass the local pitt's for rego..

after doing so many of these i've now supplyed the details (above).. if you need more details then ask...

cheers

[Esteban]

Any news on the MX13 diff + Avante disc setup? I'm keen to buy a set of your bolts and spacers as I have an F-series diff here that will eventually go into the RA23... yet to grab an Avante setup to test it though...

[Wiggles]

Great write-up GA61xx, i've been thinking about this conversion for ages. Thanks for putting it all in one place.

Just to double check a few things:
- What dimensions are the spacer rings? these are welded to the drum brake retainer plates yes?
- Is it totally necessary to use the RT142 steel lines on an RA60 diff? or can you mod the Celica lines to fit? (or use custom flexi lines to connect them)

When i start ringing around wreckers, what sort of money should I expect to pay for the corona brake setup? Just a ballpark figure would be good so i don't get ripped off.

[GA61XX]

Great write-up GA61xx, i've been thinking about this conversion for ages. Thanks for putting it all in one place.

Just to double check a few things:
- What dimensions are the spacer rings? these are welded to the drum brake retainer plates yes?
- Is it totally necessary to use the RT142 steel lines on an RA60 diff? or can you mod the Celica lines to fit? (or use custom flexi lines to connect them)

When i start ringing around wreckers, what sort of money should I expect to pay for the corona brake setup? Just a ballpark figure would be good so i don't get ripped off.

Q:- " What dimensions are the spacer rings? "
A:- copy's of the RT142's ring's....
Q:- " these are welded to the old drum brake bearing retainer plates yes? "
A:- Yes...
Q:- " Is it totally necessary to use the RT142 steel lines on an RA60 diff? "
A:- No.. but is the easyest.... they fit so why not use them...
Q:- " can you mod' the Celica lines to fit? "
A:- Yes... But you will need bending & flareing tool's... you need to have a flareing tool that will do the Double Flare...
Q:- " what sort of money should I expect to pay for the corona brake setup? "
A:- the cheeper the better..

cheers

[garyskl]

Thank you for sharing the info.
Question:
How much wider is from wheel to wheel/ or how much offset changed on the wheel than b4?

Thanks

[GA61XX]

Thank you for sharing the info.
Question:
How much wider is from wheel to wheel/ or how much offset changed on the wheel than b4?

Thanks

A:- zero change ..
well nearly there may be a differance in the thickness between the Drum & the Rotor face that mounts on the axle face.. but it would not be more than a few mm per side....
This would be on the "T" diff's.. But on the MX13/23 you would add about a couple of mm total to that..