Hi,
I have a 1969 xj6, i would like to swap it to have outboard brakes.
Can anyone advise what models of car i can look for to find parts for this?

i've read an xjs 1994-1996 XJS suspension would work?

Thanks in advance

 

Look for posts from Alynn Murray. I think he has done the swap, or has at least figured out how.

Yes, as I recall, 94-96 XJS stuff should work....but you don't really change the suspension. Just the hubs and brakes. It's fairly straightforward

Cheers
DD

 

Interesting idea. Will I do it? Not likely. Slight engineering loss and definite maintenance gain? Yeah, if swapping calipers is done often. A bit easier to change pads, yes. But, pad change in the original not all that bad. Caliper swap, oh yeah. I decided to farm mine out. Were I at least 10 years younger, mebbe.


Merely food for thought.


Is peddle Ausie for Yank pedal?


Carl

 

Some day when I get really brave I want to do that.

It will be quite some time though, because husband worked SO hard getting those calipers changed without dropping the IRS (when he gets in one of his stubborn streaks I just stand aside.) that I'll have to be Sure there's a good reason.
(';')

 

Thanks Doug

JagCad, Thank you. I have been reading about the pitfalls and benefits of the inboard brakes. I think i would prefer to leave them as is but I'm changing some things on the rear end and to keep brakes they might just have to go outboard.
Good catch on my spelling of 'pedal' i had thought bike pedals were spelt differently :/

LnrB. I will be dropping the rear cage so if anything needs doing, now is the time to do it!

 

Yeah I think you are limited to pretty much the last couple of years of the XJS...

I spoke with a former Jaguar mechanic from the 80s a while back. He said one job he loved was doing a rear disk switch on the Series 3 XJ.. When I asked why he said the hours he could bill was about 8, but he had it down to about 3... He was doing two a day and getting paid for 2 days.. His secret was the way that he dropped the wishbones and half shafts... Apparently you can remove the wishbone at the hub side, and just let it hang... then you can get to the half shaft nuts at the caliper, and just let it hang..
Having been in that area quite a bit, I can't see how you'd get the bolts clear from the calipers that easy, but I guess it's all in the technique...
But to do the whole swap from the late Facelift XJS would be costly... And how often do you have to think about calipers or disks? The pads themselves are a simple swap...

Cheers
David
shop.EverydayXJ.com

 

David:


1. I've read of the technique of "dropping" the half shafts to create working room to get at the calipers. Opening the U-joint at the inner or outer end escapes me.


2. I agree, that if the calipers are heathy, swapping pads is not all that bad. On one's back side not that good. with a lift, oh yeah.


3. I trust the rebuilds in my car will take me the "rest of the way".


Itchy:


I really wasn't poking fun at your spelling, I truly was curious. Pedals are fund in a lot of machinery. Peddle is what sales folks do, or so, that is what I think!!!
Carl

 

Exactly, and that's the reality that makes the conversion less appealing for some.

Lots of effort to replace the inboard calipers and discs but you'll be 'good to go' for many years....especially since these cars are typically just weekend/occasional use nowadays.

Outboard brakes are naturally easier to service but the conversion itself requires a fair amount of labor and expense. And though it's basically a 'bolt in' there are always details to sort out: parking brake cables, brake pipes and hoses, etc.

Decisions, decisions

Cheers
DD

 

The easiest way is to find a 1994 to 1996 XJS with outboard brakes and swap the complete rear IRS. You would need to re-engineer the brake lines arrangements a bit. One of these assemblies are rare to find out of a car.

The other practical way is to use the hub carrier from an XJ40 or even an X300. Same hub carrier. I've never actually done this but I've read on the interweb its possible. It's been said one can leave the inboard rear disks in place for proper drive shaft spacing and for E-break function.

The late calipers are metric. I simply used the early cars' T fitting, bolted it to the late IRS and put a metric fitting on one end of the extension tubes that run to the far ends of the IRS for calipers. This allow for the use of OE flexible rubber brake lines to the caliper.

The reasons for an outboard brake conversion are many but there are some things to consider.

1. You will have much greater rear brake bias since the outboard brakes are more effective. The additional rear brake bias will make the car stop much better with less nose dive. The risk is the car will tend to lock the rear brake first, this can lead to a loss of control and /or a spin. You may have to add a proportioning valve. like this one to manage this. Also wider rear tires can help. The XJS non vented outboards will be closest to stock. The XJS vented, the XJ40 and XJ300 series setups will have much more rear bias when installed.

Wilwood Disc Brakes - Porportioning Valves & Pressure Valves

2. Much easier to service and bleed the rear brakes.

3. More over the axle space for larger exhaust pipes if you need them.

4. The later hubs are webbed and stronger. The early one crack. Anyone who runs a high performance Jag with an early rear hub carrier is taking a bit risk. The picture below was mine, it cracked!

https://lh4.googleusercontent.com/-r...2013-02-01.jpg

 

It does requires lots of work and considerable expense to upgrade to out board brakes. Speaking as someone who likes to go fast and stop faster doing this upgrade is well worth it, if your car is performance orientated.

Being performance orientate myself, I despise inboard brakes. After a lot of work and expense, my experience was that when freshly installed they work great. After a short amount of time they become ineffective from oil contamination.

I've parted many old jag, I've never seen an inboard brake setup that didn't have the innder pad contaminated from leaking diff oil. It runs down the inner side of the disc, contaminates the pad and renders the inner pad ineffective. You can tell this occurs becasue the inner pad is worn much less than the outer pad.

Series 1 and 2 diff do leak. There was a slight redesign series 3 and later diffs to help address this but series 3 diff still leak a bit.

Any leaking oil from the transmission, pinion, or motor blows strait back on to the rear rotors, this also contaminates the pads with oil rendering them ineffective becasue modern oils dont burn off so easily.

 

Elinor:


Stubborn streaks are good. Some have said mine are more than a streak. I term it persistence. A good thing.


1. Jeep hatch struts in. Much better. Jeep and I went on errands.
2. Tankless water heater works. Might need more "tinker". Struggles a bit to get our cold ground water up to really hot...
3. Electric chain saw in action today. Just a tad warmer, and sorta dry. Two more green cans of slash await the recycle truck. Some set aside for firewood and projects.


Carl

 

JagCad – honestly no offence was taken !
Doug I’m going to be messing around a fair bit back there anyway so doing the conversion now will save me some time. I suspect my efforts will interfere with the position of the discs anyway so to maintain rear brakes at all they HAVE to be moved outwards.
Thankyou icsamerica
I’ve found my manual for my xj6 has the exact dimensions for the rear wishbone hub carrier end (15.5cm) if the xj40 or x300 are similar then I’ll take the gamble. I’ve asked on the other forum here if someone could look into this for me. I have found a complete rear end from an xjs but at $1500 aus plus shipping from England, I’ll hunt around a little more first! The car will have about 400hp and 600nm when I’m done and be my daily ride so while these may not be monstrous performance figures I want it to be reliable.
I appreciate the advice about brake bias, I would never have thought of that until it happened!

 

If swapping a late XJS outboard IRS into your car, be aware that the trailing arms are different too, so get them as well as the IRS.

Rob

 

With 400 HP there are a few more upgrade necessary.

Cage twist... review the link below.
https://www.jaguarforums.com/forum/x...ar-car-106032/

May want to upgrade the front brakes too... Consider a series 3 front spindle setup at the least. Series 3 has vented front rotors and larger inner bearings.
An upgrade linked below is also warranted for a performance oriented XJ
https://www.jaguarforums.com/forum/x...e-works-84536/


How are you getting to 400HP?

 

As luck would have it, I had an inquiry today about the differences in the X300/XJ40 Hub vs the Series 1-3 XJ...
I had the parts on hand to compare..
Basically as far as I can tell, the hubs are the same width (about 6 1/8")
The length of the wishbones are the same. The only difference in the wishbones is the shock mounting on the X300, and the width at the differential.
There is a major difference in the stub axle, at the end of the half shaft. My assumption would be that if you were going to switch the hubs, you'd also need at least the stub axle...
I made some notes and photos... Hope it helps..

Cheers
David
shop.EverydayXJ.com

 

That's some good info. I would imagine the Series 3 is the one with the longer splines, as they sometimes be very difficult to remove. I think you would need the complete axle becasue AFIK the later U-joins are different and just the stub can not be swapped.

 

Yes, that's correct.. the larger one is the Series 3..
Generally the hubs are pretty easy to remove through the 85 model year. After that there was a TSB that suggested the use of Loctite (or similar) to the splines on the stub axle... You can get those off with a lot of heat, but that messes up the bearings.. So normally if i'm going to pull a hub for sale, it's coming off a pre 85 car...
You are correct too about the stub axle and half shaft..
The half shafts are roughly the same length, but the opening for the stub axle is way different.. About 4 3/8" on the Series 3 vs 3 7/8" on the X300...

 

Thank you Robert, I would not have thought of that.

icsamerica
You legend, have read your brake upgrade thread several times and saved the details of those wilwood brake bits. I'm keeping an eye out for a series 3 to steel the front hubs off.
An attachment at the bottom of the cage seems like a great idea if not a necessity and those threads have great info.

Speaking of legends, David!
That inquiry was me! I wasnt sure if the info could be had on the forum so i emailed a pro. It seems the hub would work but you would need the driveshafts as well.

this info makes me confident enough to give it a go.

So exciting!

 

Hello David,


is there a difference in the openings from the xj40 hub to the series1/2/3 wishbone?

In a cobra forum I read that the wishbone's are .05" (1/16") larger than the 9/16" bolt that holds the j40 hub onto its bolt, and that either the wishbone needs to be shimmed or the bearings on the hubs need to be changed to match the original bolt.


thanks.


cds