Inboard brakes - Curiosity

Many years ago, some high bucks cars (Jaguar, I believe was one of them),
developed inboard disc brakes for their IRS rear axles. These brakes,
IIRC,
were mounted to either side of the banjo housing.

This would allow the banjo housing to be hard mounted to the chassis,
becoming
sprung weight. The swing axle assemblies were then unsprung weight, and the
figures of sprung/unspring were improved a bit.

Does anyone else remember this? Were these systems ever in large scale
production?

It occurred to me that if this sort of system were worth developing,
somebody
would have.

In a typical modern FWD system, inboard discs would be possible on the
transmission side of the halfshafts, and a rear swing axle with sprung disc
assemblies would also be possible.

This is just a thought provoker. I imagine such a system either doesn't
offer the
advantages hoped for in the past, or is just too expensive or undependable
to
implement.

wrote in article
>...
> Many years ago, some high bucks cars (Jaguar, I believe was one of them),
> developed inboard disc brakes for their IRS rear axles. These brakes,
> IIRC,
> were mounted to either side of the banjo housing.
>
> This would allow the banjo housing to be hard mounted to the chassis,
> becoming
> sprung weight. The swing axle assemblies were then unsprung weight, and
the
> figures of sprung/unspring were improved a bit.
>
> Does anyone else remember this? Were these systems ever in large scale
> production?
>

Yep! All the Jags had them, alomng with several other foreign cars.

They were not the easiest brakes to service.......



> It occurred to me that if this sort of system were worth developing,
> somebody
> would have.
>

It is still used in the rear of many RWD, formula and open-wheeled race
cars, but they also use conventional front disc brakes mounted outboard
near the wheels.


> In a typical modern FWD system, inboard discs would be possible on the
> transmission side of the halfshafts, and a rear swing axle with sprung
disc
> assemblies would also be possible.

Yep.....BUT.......

Break one cv Joint/half-shaft in a FWD car and you lose half your front
brakes.

Given that most FWD cars place up to 90 percent of their braking load on
the front wheels, that would be quite a loss.

Besides, I'm not sure the front drive assemblies are engineered to
withstand the more violent braking actions versus smoother acceleration
inputs.


>
> This is just a thought provoker. I imagine such a system either doesn't
> offer the
> advantages hoped for in the past, or is just too expensive or
undependable
> to
> implement.
>
>
>

wrote:
> Many years ago, some high bucks cars (Jaguar, I believe was one of them),
> developed inboard disc brakes for their IRS rear axles. These brakes,
> IIRC,
> were mounted to either side of the banjo housing.
>
> This would allow the banjo housing to be hard mounted to the chassis,
> becoming
> sprung weight. The swing axle assemblies were then unsprung weight, and the
> figures of sprung/unspring were improved a bit.
>
> Does anyone else remember this? Were these systems ever in large scale
> production?
>
> It occurred to me that if this sort of system were worth developing,
> somebody
> would have.
>
> In a typical modern FWD system, inboard discs would be possible on the
> transmission side of the halfshafts, and a rear swing axle with sprung disc
> assemblies would also be possible.
>
> This is just a thought provoker. I imagine such a system either doesn't
> offer the
> advantages hoped for in the past, or is just too expensive or undependable
> to
> implement.

In-board brakes were one of the many enhancements made to GP type cars
many years ago. Certain high-end car manufacturers incorporated them
more as an image enhancer (I think) than anything else. The
drivability of cars like the Jag was not measurably enhanced and I
suspect car makers could not really see that their addition improved
sales. An expensive not-visible addition was dropped.

> wrote in message
.. .
> Many years ago, some high bucks cars (Jaguar, I believe was one of them),
> developed inboard disc brakes for their IRS rear axles. These brakes,
> IIRC,
> were mounted to either side of the banjo housing.
>
> This would allow the banjo housing to be hard mounted to the chassis,
> becoming
> sprung weight. The swing axle assemblies were then unsprung weight, and
> the
> figures of sprung/unspring were improved a bit.
>
> Does anyone else remember this? Were these systems ever in large scale
> production?
>
> It occurred to me that if this sort of system were worth developing,
> somebody
> would have.
>
> In a typical modern FWD system, inboard discs would be possible on the
> transmission side of the halfshafts, and a rear swing axle with sprung
> disc
> assemblies would also be possible.
>
> This is just a thought provoker. I imagine such a system either doesn't
> offer the
> advantages hoped for in the past, or is just too expensive or undependable
> to
> implement.

Early Jag inboard brakes required dropping the rear crossmember to service.
Later versions were only slightly more accessable. Both suffered when the
brakes overheated the oil seals on the final drive and oil leaked onto the
rotors. The Audi 100LS is the only FWD I recall that had inboard front
brakes. Changing pads on cars with auto trans was difficult and oil leaks
onto the brakes were common. The layout thwarts cooling air from doing its'
job resulting faster wear of the already soft German rotors and the drive
axles must be removed to change them. In the few years these cars were on
the road (they had many other problems) I never witnessed a broken axle.

"Chas Hurst" > wrote in message
...

> Early Jag inboard brakes required dropping the rear crossmember to
service.
> Later versions were only slightly more accessable. Both suffered when the
> brakes overheated the oil seals on the final drive and oil leaked onto the
> rotors. The Audi 100LS is the only FWD I recall that had inboard front
> brakes. Changing pads on cars with auto trans was difficult and oil leaks
> onto the brakes were common. The layout thwarts cooling air from doing
its'
> job resulting faster wear of the already soft German rotors and the drive
> axles must be removed to change them. In the few years these cars were on
> the road (they had many other problems) I never witnessed a broken axle.

The only Jaguar I ever personally considered owning was an XK-E, slightly
used in the 1960's. Compared to anything else I had ever driven, this was
like a dream...fantastic roadworthiness, fine acceleration,etc.

Then, before I bought, I found that they were typically British of that
era..
burned a lot of oil, expensive to work on, stone age electrics,not so very
reliable.

I am very interested in what the companies have done in the last few years
to make such dramatic improvements in body integrity, driveability,
quietness.

We have driven Buicks a lot, and they are fairly comfortable and roadworthy
cars, but still with a little objectionable noise, body integrity okay but
not good,
a slight about of jitter at highway speed. But, compared to earlier Fords I
have
known (up through 1990 Thunderbirds) , Buick was a jump step better.

(Notice, I do not brag on some of GM's engineering. Some engines, trannies,
electrics, etc are terrible.)

I have test driven Toyota Camry and Volks Passat recently and am truly
amazed
at the improvement over what I am used to.

Perhaps these manufacturers have just taken a lot of care with many small
things
but the perceived feel, to me, is as if they have made quantum improvements.

Chas Hurst wrote:

> The Audi 100LS is the only FWD I
> recall that had inboard front brakes.



Also the Citroen 2CV.

Hugo Schmeisser > wrote:
>Chas Hurst wrote:
>
>> The Audi 100LS is the only FWD I
>> recall that had inboard front brakes.
>
>Also the Citroen 2CV.

The 2CV has brakes? I thought you just stuck your foot through the hole
in the floorboards to stop it?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:

> Hugo Schmeisser > wrote:
> > Chas Hurst wrote:
> >
> >> The Audi 100LS is the only FWD I
> >> recall that had inboard front brakes.
> >
> > Also the Citroen 2CV.
>
> The 2CV has brakes? I thought you just stuck your foot through the
> hole in the floorboards to stop it?



So that's what Fred Flintstone drove...

"Hugo Schmeisser" > writes:

>> The Audi 100LS is the only FWD I
>> recall that had inboard front brakes.
>
> Also the Citroen 2CV.

....and the Volkswagen K70. Front wheel drive, inboard disks on front,
regular drums on rear wheels. Could be scary in wet weather: I soon
learned to dry the rotors with my left foot on the brake pedal after
driving through puddles of any size.

-tih
--
Don't ascribe to stupidity what can be adequately explained by ignorance.

In article >,
says...
>
>
>"Hugo Schmeisser" > writes:
>
>>> The Audi 100LS is the only FWD I
>>> recall that had inboard front brakes.
>>
>> Also the Citroen 2CV.
>
>...and the Volkswagen K70. Front wheel drive, inboard disks on front,
>regular drums on rear wheels. Could be scary in wet weather: I soon
>learned to dry the rotors with my left foot on the brake pedal after
>driving through puddles of any size.

Alfa Romeo Milano's and GTV rear inboard brakes. Inboard brakes are harder to
work on than regular ones. I think one reason you don't see that that much is
that there is not that much air flowing under the car to cool the brakes. So
outboard brakes are preferred.
--------------
Alex