Will this work?
Husband wants to have a center section built up 'in reserve,' because that's how he is. We know the gears are different but he thinks the 700R4 will make up for that.

There's a likely S3 candidate just received into his favorite wrecking yard and he thinks we can have the pumpkin in hand by tomorrow afternoon.

I'm told to ask if the S2 stub shafts will fit, if the S2 drive shaft will fit, how much more trouble (not to mention time) are we looking at?

Any other words of wisdom from those more experienced than we are will be Greatly appreciated.
(';')

 

Elinor,

YES.

The V12 versions ran a larger pinion flange (from memory).

Half shafts etc are all the same.

Brakes are identical.

Lower cast brackets are the same.

Cant think of any negatives.

 

Thank you, Grant!
We'll fall by today to take a look.
(';')

 

It was HOT in the yard by the time we got there. Not even pleasant!

The diff (and the whole car) was in Way bad condition. Husband decided to leave it there and look for 94-96 XJS rear suspension with outboard brakes.

I'm not holding my breath.

But it wasn't a total loss, I got the Opticell socket & reflector and a hand full of black trim screws with matching trim washers.
(';')

 

The XJS outboard rear brake setup is much better. So much so that the rear brake bias will be way off. The rear brakes will tend to lock quickly which can be dangerous on a non-abs car. You will have to add ABS (easier than you think) or use an adjustable Wilwood proportioning valve on the rear circuit.

 

Iso:


Why would moving the rotors and calipers to an outboard position make them sdo much better so as to affect front to rear bias?


And, was/is a the engineer's reason for inboard brakes, a reduction of unsprung weight. A good part of IRS vs live axle choice.


Don't mean to open the in vs out controversy. Service an obvious reason!!


Elinor


I'll bet. Removing the cage from a derelict car in wrecking yard conditions, tough at best. In high heat. Nope for a lot of reasons.


Although, the car was junky. You and hubby would have rebuilt the thing from stem to stern anyway!!! Bearings, U joints, calipers, bushings, the works.


But, The "pumpkin" is only the differential casting and it's "guts", not the entire cage. A Dana 44 in essence, as tough as they come.


Jaguar relay redo gong well. proceeding slow and methodical.


Carl

 

icsamerica:
Thank you So much! I didn't know the bias would be affected with XJS brakes! On the farm we set up the old trucks that had no auto adjusters so the rear brakes were tighter than the front, so that wouldn't be new to me.

I've read your thread about brake upgrades from 2012 and have it bookmarked. I don't remember mention of the Wilwood valve but I'll make a note of that too.

Carl:
Quite frankly I questioned his decision to do that under the conditions in that yard. Imports are the Farthest from the front gate, about 1/4 mile, the ground is covered with 1-1/2 inch "crushed" rock with all the sharp points up and the only shade is under the car. Being there during the heat of the day was only the last straw.

He'll find Just the right one that suits him eventually, but until then I'll be content with getting brakes operational.

Besides. He already got both rear calipers out while I was gone yesterday. I'll be writing that up in Rolling Stock next week sometime, as we're taking Wart (how humiliating!) on the club drive to the Muir Woods Saturday.
(';')

 

That is true, I did not use the Wilwood perportioning valve for two reasons. First... There was no need for it in my case...I was planning to install a Bosch ABS II system. I did so successfully a few weeks after I installed the outboard brake using a late XJS IRS. Second...I upgraded to larger front rotors and Wilwood calipers which were a better match for the late XJS rears. This restored a more neutral braking bias.

 

Carl...it's a good question and the all things being equal there should be no difference. But there is because the piston on the XJS outboard brakes has more area and thus more clamping force. Also the outboard brake rotors are larger in diameter so there or more mechanical advantage on the rotor. All that add up to much greater rear braking bias. The end result is a much better braked vehicle that tends to dive much less under hard braking. Car with more rear bias need ABS to be safe though.

In theory inboard brakes are great for un-sprung weight reduction...as a practical matter they are not any good. The diff, engine, trans all weep oils and that oil blows back and tends to collect on the rotor and contaminate the pads rendering the rear brakes mostly ineffective. The rotors get hot which tend to cook the diff seals, that exacerbates the oil weep / rotor contamination issue. An outboard rotor uses the road wheel is a large heat sync that has the advantage of moving through cool air and is far away from any exhaust pipes.

I observed No noticeable decrease in ride quality or road holding after installing the outboard brakes. I think modern tires are just all around better now.

 

So, it is a better brake rather than location that makes the difference.


Disk brakes do much better in high heat than do drum brakes.


But, a highly developed drum system beats a poor disk set up.


Now, if the Jaguar engineers had done a better job of the hand brake system....


Mine have not been the same since the caliper swap out. Going down and in is so far down the list so as to probably never happen.


Elinor:


Setting the rear brake a tad tighter was to prevent front wheel lock and loss of steering.


Very early big rig truckers refused to have front brakes at all. Prefering top be able to lock up the 8 drivers and steer the front ones.


Carl