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Inboard Rear Brakes
scootz - 19/11/09 at 01:49 PM

Anyone done this on a Se7en???

If so, how did you get on?


britishtrident - 19/11/09 at 02:00 PM

Colin Chapman did it 50 years ago.


scootz - 19/11/09 at 02:00 PM

How did he get on?


britishtrident - 19/11/09 at 02:08 PM

Not sure. he used them on the first Elite but abandoned them for the Elan.

Inboard brakes & de Dion go well together -- To be a true puka de dion inboard brakes are part of the package.

However I have a strong distrust of inboard brakes due to exposure to Jags and 1960s Rover.

Easiest way to fit in board brakes is to start with the complete rear axle assembly of a 1970s Elite/Eclat/Excel.

Big problem is mounting them on a diff not designeened for the job, drive shaft also have to be up to the job.



[Edited on 19/11/09 by britishtrident] Rescued attachment 4.JPG
Rescued attachment 4.JPG


blakep82 - 19/11/09 at 02:12 PM

if you took an axle from a Jag for example, i can't see it would be a problem. but is it really worth the hassles? what are the benefits of inboard brakes?


britishtrident - 19/11/09 at 02:16 PM

quote:
Originally posted by blakep82
if you took an axle from a Jag for example, i can't see it would be a problem. but is it really worth the hassles? what are the benefits of inboard brakes?



Jag axles are mega heavy ---- really 4 man job to lift say an E Type or 70s XJ6 rear end assembly.

70s Lotus Elite Axle had drum brakes
see ebay item 190345534348


scootz - 19/11/09 at 02:17 PM

I'm changing the Quantums rears from drums to discs... the factory want £500 for their kit (which includes Sierra calipers), but I:

a) don't want to pay that!
and
b) don't want to be using Sierra calipers!

I'm just trawling through all other options (before I go and buy stuff that's not up to the job, then have to buy the Quantum kit anyway and then have to flog all the unusable bits I no longer need on here for a fraction of the original cost! ).


whitestu - 19/11/09 at 02:29 PM

Alfa brakes?

A lot of RWD Alfas had inboard brakes at the back - 75s etc. Alfasuds also had inboard discs at the front with a handbrake mechanism.


MK9R - 19/11/09 at 03:03 PM

Assuming you have bolt on seirra driveshafts, could you not just get some lightweight discs and calipers and sandwich them between diff and driveshaft, then make a simple bracket to mount calipers to chassis. it reduces the unsprung weight a fair bit.

[Edited on 19/11/09 by MK9R]


blakep82 - 19/11/09 at 04:07 PM

quote:
Originally posted by MK9R
Assuming you have bolt on seirra driveshafts, could you not just get some lightweight discs and calipers and sandwich them between diff and driveshaft, then make a simple bracket to mount calipers to chassis. it reduces the unsprung weight a fair bit.

[Edited on 19/11/09 by MK9R]


wouldn't tkat put a lot of stress on the driveshafts that they weren't designed for?
i don't know, i can't get my head round it


MK9R - 19/11/09 at 04:10 PM

quote:
Originally posted by blakep82
quote:
Originally posted by MK9R
Assuming you have bolt on seirra driveshafts, could you not just get some lightweight discs and calipers and sandwich them between diff and driveshaft, then make a simple bracket to mount calipers to chassis. it reduces the unsprung weight a fair bit.

[Edited on 19/11/09 by MK9R]


wouldn't tkat put a lot of stress on the driveshafts that they weren't designed for?
i don't know, i can't get my head round it


is it anymore than hard acceleration, especially as its the rear brakes and the fronts are doing most of the work??????


lsdweb - 19/11/09 at 04:14 PM

I've been toying with this for the Westfield. Main advantage is reduced unsprung weight. Main disadvantages -
getting discs to fit on a Subaru diff.
Cooling of the discs and calipers (as the car will have a flat floor and rear diffuser so no flow of air.

Wyn


MK9R - 19/11/09 at 04:21 PM

quote:
Originally posted by lsdweb
I've been toying with this for the Westfield. Main advantage is reduced unsprung weight. Main disadvantages -
getting discs to fit on a Subaru diff.
Cooling of the discs and calipers (as the car will have a flat floor and rear diffuser so no flow of air.

Wyn


You could easily fit a scoop onto the flat floor (or rear deck) and channel air directly onto the discs. Are scooby diffs push in driveshafts then?


blakep82 - 19/11/09 at 04:38 PM

quote:
Originally posted by MK9R
quote:
Originally posted by blakep82
quote:
Originally posted by MK9R
Assuming you have bolt on seirra driveshafts, could you not just get some lightweight discs and calipers and sandwich them between diff and driveshaft, then make a simple bracket to mount calipers to chassis. it reduces the unsprung weight a fair bit.

[Edited on 19/11/09 by MK9R]


wouldn't tkat put a lot of stress on the driveshafts that they weren't designed for?
i don't know, i can't get my head round it


is it anymore than hard acceleration, especially as its the rear brakes and the fronts are doing most of the work??????


it was what BT said at the top that made me wonder, and also why i said i can't get my head round it


Mave - 19/11/09 at 04:48 PM

search posts for erwe. His car:


scootz - 19/11/09 at 05:07 PM

That's exactly what I was looking to do!

ta!


britishtrident - 19/11/09 at 05:36 PM

quote:
Originally posted by scootz
I'm changing the Quantums rears from drums to discs... the factory want £500 for their kit (which includes Sierra calipers), but I:

a) don't want to pay that!
and
b) don't want to be using Sierra calipers!

I'm just trawling through all other options (before I go and buy stuff that's not up to the job, then have to buy the Quantum kit anyway and then have to flog all the unusable bits I no longer need on here for a fraction of the original cost! ).


Don't knock Sierra rear calipers they are near ideal for the job and although cast steel not that heavy.

Dear disc brakes were a right PITA for years nobody really got the handbrake to work properly, but the style of caliper on the Sierra and most other cars of the 80s & 90s has been the by far most successful solution

[Edited on 19/11/09 by britishtrident]


britishtrident - 19/11/09 at 05:42 PM

quote:
Originally posted by MK9R

is it anymore than hard acceleration, especially as its the rear brakes and the fronts are doing most of the work??????


By using the shafts for braking as well as acceleration they get subject to much higher amplitude load reversals.


britishtrident - 19/11/09 at 05:45 PM

quote:
Originally posted by MK9R
Assuming you have bolt on seirra driveshafts, could you not just get some lightweight discs and calipers and sandwich them between diff and driveshaft, then make a simple bracket to mount calipers to chassis. it reduces the unsprung weight a fair bit.

[Edited on 19/11/09 by MK9R]



The calipers must be mounted on the diff and the mounting must be very ridgid, likewise the diff mountings need to be up to the job. Floating calipers make more sense than opposed piston because the diff shaft will tend to float about a lot.