on June 12, 2010, 12:38 am, Daze wrote:

well I weighted all day for you to show up before I opened the box
  OK I learned a lot. I got a set of X308 or 99 XJ8 hubs and half shafts asI could not find any XJ40 or X300 parts. There are some things that will be a little harder to overcome than others. From behind the only main differences are the brake cable and the splash shield. 

From the front there are some noticeable differences, the biggest of which is the the integrated parking brake. This poses one major issue, it requires the specific Jaguar rotor and there is an adjustment hole drilled in the hub. These two things make re-drilling the hub out of the question so bolt pattern adapters will need to be used


According to the info I had the XJ40 hubs require a spacer between them and the wish bone because the XJ40 hub is slightly narrower, but when I fit the hub in to the wish bone it was a nice tight fit. The pins however are a different size so I will either have to bore out the the bearing sleeve by .050 to accept the XJ6 pin, or machine some UHMW bushings to fit in the hub and accept the bigger shaft. I am leaning toward the second option

The half shafts are the exact same length as the XJ6 units but unlike the info I had that said the u-joints are the same, they are actually different. the cap size is the same but the width of the u-joint is about 1/2" smaller. good news is I will be able to use the new half shafts in their entirety.

on June 12, 2010, 10:16 am, Daze wrote:

The rotor is not that big of a deal, just one more thing to drill
the biggest issue is the adjuster hole for the parking brake. the hole is right where the new pattern will need to be. I highlighted the hole in the picture.   

Also I forgot to mention that the flange is different thicknesses where the studs are as apposed to where they need to go for the Ford pattern. you can kind of see it in this pic. The bump on the back side of the wheel flange in the picture is not the wheel stud

on June 12, 2010, 4:34 pm, Mustsed wrote:

OK, now I understand what you mean and to............ sad that adapters are needed.

I found the local guy who is parting out old Jaguars and hope to get in contact with him on Monday and see if he has the parts to convert to outboard discs.

on June 13, 2010, 5:40 pm, tyrellracing wrote:

On your out board disk brake hub carriers, did they change the hub carrier bearings? I was curious weather you could simply swap hubs, keep your old half-shaft assembly's and re-drill the rotors to the 5 on 4 1/2 bolt circle?

on June 14, 2010, 10:23 pm, tyrellracing wrote:

I found that the dramatically reduced unsprung weight of the Jag setup to be one of its best attributes. Did you choose to go with the out board disks to aid brake cooling only or were there other factors like the parking brake? The old style lower control arms were designed with the idea that they would not be exposed to the brakes torsional loading on top of the fore and aft forces from braking and acceleration. Since hard braking can produce large amounts of torsional loading, didn't the out board disk brake get a much heavier and larger design control arm? I am curious weather this combination will generate wheel hop due to the lower control arm twisting under hard braking? Do you know of anyone who has tried this combination? Were you planning on using a trailing arm similar to the stock xj6 but with the leading pivot moved inboard to a tangent line with the inner pivot of the LCA? This design would control the fore and aft loading of the LCA. This might be beneficial for the out board brakes on in board brake control arms. This is in no way a criticism, if this combination works good for your application all I can say is job well done! But there are some variables involved in this hybrid setup that may create some unwanted side effects. With the torsional stiffness of the large diameter tube of the LCA may not. I think that dynamic testing will be the only real proof of compatibility. I will openly admit one thing, bleeding and pad replacement on inboard disks is a pain in the ass. I have never liked solid rotors due to their inability to dump heat quickly. This weekend I took my car out for a little hard cornering. After 25 minutes of max effort braking coming into corner apexes, my brakes began to fade. The fronts were fine but the jag brake limits were exceeded. I feel this was from boiling brake fluid and/or inferior pad material. The scoops on the sides of my car don't have very large openings but with the ducting do produce some cooling to the rear brakes. Do you know of anyone who has converted the jag brakes to a vented rotor 4 piston caliper configuration? Making vented rotors from billet is difficult and very time consuming. Finding rotors greater than.875 thick with a small enough center hole and a large enough OD is so far illusive. Late eighty's Subaru front rotors are the only ones even close on ID but in my opinion are too thin when new. Rotor hats or com-posit rotors with welded in centers look like my only options so far. Do you have any opinion on this?

on June 15, 2010, 10:12 am, Daze wrote:

Thats a lot of questions Man I love having an IRS forum questions are what it is here for!!!
First of all I do not plan on going with the out board discs on my Mustang. On that car I want it to be as "light on its feet" as possible so unsprung weight is an issue. It is my 62 Galaxie that will be getting the outboard discs.

I found that the dramatically reduced unsprung weight of the Jag setup to be one of its best attributes. Did you choose to go with the out board disks to aid brake cooling only or were there other factors like the parking brake?

There are a lot of reasons for me to doe it:

thicker rotor

vented rotor

better parking brake

easier access to brake parts (for the Galaxie that is a big one)

wanting my Jag installs to be as complete as possible, in other words I want to have experience with more than one way to do it

The old style lower control arms were designed with the idea that they would not be exposed to the brakes torsional loading on top of the fore and aft forces from braking and acceleration. Since hard braking can produce large amounts of torsional loading, didn't the out board disk brake get a much heavier and larger design control arm?

In 1988 when Jaguar made the change from inboard to outboard they used the same basic wishbone design. If you think about it regardless of where the brakes are located the "stopping" force is transfered to the tires so where the tire meats the road will always be where the forces are at. From the inboard brake to the wheel is basically solid so it really doesn't matter "torsionally" wither the brakes are inboard or out board. One improvement however is less stress on the u-joints. By moving the brakes outboard there is no stress on the u-joints when braking.

I am curious weather this combination will generate wheel hop due to the lower control arm twisting under hard braking?

I do not know for sure, but I have not heard of this being an issue. I would assume that since Jag did it with the same basic suspension and that since rca replicas and CWI have done it that there is little to no performance loss.

Do you know of anyone who has tried this combination?


Oh yes. this is a VERY popular mod in the Jaguar racing community ever since the XJ 40 came out in 1988 which means this upgrade has been seriously put to the test for a long time.

Were you planning on using a trailing arm similar to the stock xj6 but with the leading pivot moved inboard to a tangent line with the inner pivot of the LCA? This design would control the fore and aft loading of the LCA. This might be beneficial for the out board brakes on in board brake control arms.

I am not only planning to do that on my 62 Galaxie with the outboard discs but also on my Mustang with the inboard discs. my trailing arm set up will be very similar to this:

This is in no way a criticism, if this combination works good for your application all I can say is job well done!


I wouldn't have it any other way and this is EXACTLY why I created this forum. 2 heads are better than one and a group of like interested people will provide enough perspectives to eliminate many issue before they happen. Besides having to defend something is a great way to really understand what you are doing. I not only appreciate the concerns and constructive criticism, I EXPECT IT!!! Thanks!!!

I will openly admit one thing, bleeding and pad replacement on inboard disks is a pain in the ass.


And that right there is the single biggest reason I began looking in to this in the first place. Since I am not using the cage on the Mustang, getting to the inboard brakes will not be that big of a deal but on the Galaxie I am using the cage and at that point simple is a priority!!!

Do you know of anyone who has converted the jag brakes to a vented rotor 4 piston caliper configuration? Making vented rotors from billet is difficult and very time consuming. Finding rotors greater than.875 thick with a small enough center hole and a large enough OD is so far illusive. Do you have any opinion on this?

There are several inboard disc brake options
Terry's JAg sells a kit
CWI sells a kit



Here are several pages from the Jaguar forum with lots of good info:
http://www.jag-lovers.org/xj-s/book/InboardBrakeUpgradeRotors.html
http://www.jag-lovers.org/xj-s/book/InboardBrakeUpgrade.html

I look forward to hearing all you thoughts on this.

on June 17, 2010, 7:49 pm, Joe wrote:

Moment about a torque I have really enjoyed your knowledge/expertice and while I have not always grasped all of the details of your posts this one hit home. Thanks!

on June 19, 2010, 6:17 pm, tyrellracing wrote:

The rotors that are displayed on the site you recommended would be very simple to reproduce. With a lathe it would be a simple matter to remove the center of a conventional type rotor then drill the flange with an appropriate bolt circle. For their brake hat they wound up with a simple disk that I feel would also be simple to reproduce. Great idea but I would rather make my own than pay for these parts. More vendors loose my business by showing pictures of their products.

I haven't done anything with it yet.  Those brakes are going on the IRS that I plan on putting under the Galaxie.  The plan at this point is to go with new OEM type rotors and then use bolt pattern adapters between the rotors and the wheels to have them be the correct bolt pattern for my ford wheels.

37ford wrote:

So, it sounds like what you have done between the two units will be what I want to do with one: narrowingan XJ6/12, gear change, traction control, and outboard disc brake conversion from an XJ40.   I'll be expecting a full parts list and an illustrated manual. 

Yep, I narrowed a series I XJ6 unit, then installed an aubern gear limited lip differential.  As to the out board discs, the hubs for the Xj40 X300 and X308 are all the same BUT the Xj40 rotors are 1/2" solid units.  I would recommend going with the X300 or X308 units as the rotors are vented and coming off newer cars they will probably be easier to find.

Mustsed wrote:

Hi everybody,

Today I re-read this post and couldn't find the info about the Hub-to-LCA shaft OD issue. I tought I read it here before but either I get older or I get older.
Anyhow, on the swap I did to outboard disc brakes, the hub to LCA shaft OD was different from each other and I had to make some bushings from this space material we were discussing in the old forum. I got the parts from a Jaguar salvage yard owner and I don't know off which jaguar they are but there is a difference in the Hub-to-LCA shaft OD.

Just to point this out!

Mustsed

Excellent point.  Good news is you are correct the info was there hidden between two pix, like you thought (not a symptom of age) , bad news is you missed it the second time you read through it (symptom of age??)   More than anything I think you probably missed it because the guy who made the original post was not very clear as to what he was saying.  Who let that guy on the forum anyway?? 

on June 12, 2010, 12:38 am, Daze wrote:

According to the info I had the XJ40 hubs require a spacer between them and the wish bone because the XJ40 hub is slightly narrower, but when I fit the hub in to the wish bone it was a nice tight fit. The pins however are a different size so I will either have to bore out the the bearing sleeve by .050 to accept the XJ6 pin, or machine some UHMW bushings to fit in the hub and accept the bigger shaft. I am leaning toward the second option

The rotors I wound up using were from an 84 mustang GT with the hubs machined out.  On this particular rotor the bearing hub and the rotor were one casting. After removing the hub from the rotor on my lathe, this design gave me more cast iron where I needed  for drilling and tapping the eight 5/16-18 holes for the hat attachment.  I made a simple disk at first then I made an off set hat so I could relocate the brakes aprox. one inch outward and create more room for the T-5 single inner pivot point. 
   The rotors I used were used from an old car I drove into the ground then dismantled and scrapped.  They were rough but after the clean up they were very close to .875 thick, vented and a little bigger OD than the Jag units.  The proximity of my X member was the limiting factor on bigger OD rotors.  The calipers I am using are Kelsey Hays 4 piston calipers that came stock on the front of 67 mustangs.  I machined them for stainless sleeves and pistons years ago. The pistons are now two different sizes per caliper for leading and trailing pistons.  This evens out pad wear.

I agree the newer parts are cool.  so much so that I am thinking about using a set of newer hubs, stripping off all the outboard disc parts, and putting them in  my Mustang but still retain the inboard discs.  in other words I want to use the newer hubs because the caliper mount and the ABS sensor hole give me a natural place to mount an upper watts bracket.   The stub axle is totally different it is radios cut, cone centered, and much more splines, not sure the exact count.  I have not pulled my hubs apart but I do know it is as you said torque  it down and be done with it.

I think I'm going to utilize C-4 Corvette outers and trailing links instead. They seem to be inexpensive compared to the later model Jag outboard brake parts, and the trailing arms negate the need for the watts linkage. I'll have to change how the lower arm (dogbone) mounts, but I think it will end up nice.

Cool project!
Bill