inboard brakes

[rick-l]

I was just wondering why with the proliferation of AWD cars you don't see inboard (sprung weight) brakes like the rear brakes of an old XKE.

[RallyJon]

Cooling? Space? I bet the new AP Racing (or is it Brembo?) multiplate brakes would be perfect for use inboard if you could get lots of air to them.

[island911]

because the axle becomes a torsion-bar.

[rick-l]

Originally posted by tcar
or front brakes on the old Audi 100.

Brake cooling.

Do you mean the front discs that had the caliper anchored on the inside of the disc and and the disc looked like a big saucer? Some people call them UFO brakes because of this.

I understand they are super heavy, super expensive, and warp super easy. aside from that they were great.

[rick-l]

Originally posted by island911
because the axle becomes a torsion-bar.

Seems fixable.

[tcar]

Originally posted by rick-l
Do you mean the front discs that had the caliper anchored on the inside of the disc and and the disc looked like a big saucer? Some people call them UFO brakes because of this.

I understand they are super heavy, super expensive, and warp super easy. aside from that they were great.

Sorry, I meant the old, old Audi 90. Had inboard brakes on the front, next to the engine. Pads lasted just a few thousand miles because they suffered from the heat.

I meant that brakes are easier to cool at the wheel, than inbooard.

With inboards, the axle shaft twists when you brake.

[rick-l]

Originally posted by tcar
Sorry, I meant the old, old Audi 90. Had inboard brakes on the front, next to the engine. Pads lasted just a few thousand miles because they suffered from the heat.

I meant that brakes are easier to cool at the wheel, than inboard.

With inboards, the axle shaft twists when you brake.

I didn't realize Audi's had inboard brakes. I just went into rant mode because I have issues with the needlessly complicated Audis I own.

Seems like if the brakes were not unsprung weight the brakes could be massive solving the cooling issues.

The springiness in the axles could be reduced or damped out also.

[tcar]

Audis have not had inboard brakes since the 70's - the original Audi 90, the first one that VW/Porsche imported. In fact they changed to outboard brakes mid production.

[Mr Beau]

Break an axle or CV and brakes no worky. I think an F1 driver died a few years back due to this.

[Superman]

I think the Jaguar axles that Island mentioned did not involve CV joints. They were a big, standard axle. In fact, drag race guys used to love to bolt those old Jaguar rear ends on their dragsters. Very robust, those things.

[island911]

I mentioned Jaguar axles?

Well, if the Jaguar axles did not involve CV joints, then there really isnt an unsprung/sprung weight advantage. . . just the disadvantages.

[Victor]

.......also allows Jaguar mechanics to charge an extra day and a half's labour to change the rotors.

[tcar]

XKE didn't have CV joints, it had U-joints on the half shafts. Strong.

[Mr Beau]

Ok, CV or U-joint, if it breaks, no more breaking... Is it a big risk? Probably not, but it is something that has to be taken into account.

[Joeaksa]

Originally posted by Victor
.......also allows Jaguar mechanics to charge an extra day and a half's labour to change the rotors.

You are not far off! Its not 1.5 days but its not an hour or two either. The reason it takes a bit is that its impossible to R&R the rear rotors in the car.

You have to pull the entire rear end cage with the entire rear suspension and rear end. One brake cable, one hyd brake line and 14 bolts. The bear about pulling it out is that the exhaust pipes go through the assy and they have to be pulled out as well. A good wrench can have one out in less than an hour.

45 minutes for each rotor (plus or minus) and then put it all back together and most experienced mechanics can get this done in 4 hours or so. My '69 XJ went almost 100,000 miles on one set of rear brakes so this is not something that is done ever month or two.

JoeA

[Victor]

Too right. Then ofcourse there is the never ending list of other things that "we found needed doing while we where down there........"

I loved my XJ though - mostly thanks to the noise of the gear driven 350 chev up the front though.......

[Joeaksa]

Not at all surprised that you had a "lumped" XJ! Real men keep the original style of engine in their cars. Thats as bad as putting a V8 Chevy in a 911!

I had a "lumped" '72 model and liked it but it was just not the same. Have owned them on and off for 30 years and love the car and have no problems what so ever with reliability using the Jag engine. My '69 model has over 660,000 miles on it with no major problems.

If I were going to change out the engine would try an XK-8 V8 engine before going with the Chevy but then thats me...

JoeA

[Victor]

Originally posted by Joeaksa
Not at all surprised that you had a "lumped" XJ! Real men keep the original style of engine in their cars. Thats as bad as putting a V8 Chevy in a 911!

JoeA

Looks like we will never be able to agree on anything.

A 911 is a work of art, cast from Germanic steel in a Teutonic forge under the watchful eye of the Porsche Gods. A 911 should preferably never even be PARKED in the vicinity of inferior man made machinery of such lowly order as a Chevrolet - let alone have such components stuffed up it's posterior.

An old XJ series Jag on the other hand? Common as muck, heavy as lead, hand wired by the prince of darkness himself and propelled by a power plant best suited for use as boat anchor. (OK, the V12 E-Type is an exception).

[Joeaksa]

I have over 600,000 miles on my '69 XJ and its let me down one time on the road, so its more reliable than my 911. One thing, I did replace that "Lucas prince of darkness" alternator with a Chrysler unit back in the '70's and no electrical problems since.

We can agree on something.... the 911. When are you going to sell the Subie and get a real car again? Then at least you will have a reason to be on this forum...

Joe A

[Mr Beau]

If a GM trans was good enough for Jaguar, why not the engine that goes with it...? ;-)