Radius arms. which side is up - IRS First Time Rebuild

(Foggyoo) #122

My xjs has about 1-2mm lateral movement at the tread, this is OK?

(Frank Andersen) #123

1 - 2mm seems a bit much, Foggyoo - I ‘think’ you should check bearing play…

However, it may also be caused by play in other areas - to be checked as well…?

xj6 85 Sov Europe (UK/NZ)

(Matt Furness) #124

I would say the jury is out on that amount of play…
I have just rebuild my rear end. New bearings, all tight press fits into their positions, new spacers machined to give 0.002" axial clearance with the axle spline torqued in position, all new universal joints in the driveshafts while they were out. Both sides have a small amount of movement at the tyre tread. I dunno how many millimetres it is…but is is more than my modern cars…which have NONE… I don’t see or feel any movement in the diff output shaft…and the reason I re-did all this is the WOF test stated wear in rear bearings !!! I am not redoing any of this stuff again so I am thinking that some movement detectable,at the tread diameter is normal. The 0.001-0.003" end float in the bearings MUST have a consequence at the wheel outer diameter. I am thinking I did all the refurbishment for no reason other than a mechanic thinking my XJS rear end should be as firm as a modern rear end!!! And I believed him…

(Matt Furness) #125

Correction…I was pondering the source of my “loose” wheel and did a few quick and dirty numbers on the bearing clearance. Making a few reasonable assumptions I reckon that the 0.003" bearing clearance would make for a wheel movement at the outer edge of the tyre of about just less than 1mm!!! Not as much as I was hoping for!!! I’ll have to check how loose “loose” actually feels. Maybe I have a tiny amount of play in the diff output shaft and the whole shebang contributes to a “loose” wheel…except the bearings would be there at 9 and 3…hmmmm…I’ll have to check if there is a difference in looseness at different locations to figure the source out…

(Mark Lee (Pay Pal Patron)) #126

Status update
I got the U/Joint covers cleaned and painted
half shafts clean, painted, and the U/Joint pressed into one side
The brakes are off and cleaned

Back to the carrier boondoggle.
I got the bearing off the hub. Much to my surprise it came off pretty easily. the bearing was sacrificed, unfortunately.

More questions
I was expecting the bits behind the bearing (seal seat & water guard - thrower, water thingy :confused: ) to fall off or at the very least be able to pull off. not the case.
Here’s a video with more questions.

Thank you in advance

(Robin O'Connor) #127

Matt, one thing to keep in mind is that there are different qualities in the U/J’s when you check for movement get some one to pry the U/J’s apart and see if the movement is still there. If there is a small amount of play in each bearing it is going to add up.

(Robin O'Connor) #128

Mark, try some heat around the outside of the ring and once there is some heat in there get a freee spray and throw that down the splined area. The combination of heat and cold may be enough to release the ring.
I am fairly sure that it should be loose when it was first assembled.

(Frank Andersen) #129

In principle, Matt; with the hub carrier stable, the only tyre ‘wobble’ would be from bearing play - whichever push/pull position is applied to the tyre.

However; with slack in the wishbone bearings the hub carrier will also move - and wheel wobble will increase. The push/pull position may indicate the likely slack points - there should be none with only human force applied. Any hub carrier movement implies outer or inner pivot wear - though 6/12 o’clock motion may also involve universal joint wear. Point is that the wishbone and driveshafts work together to maintain wheel camber through the hub carrier…

There is also the for-and-aft test, again with no hub carrier movement - any movement implies inner pivot slack. However, with the wheels off the ground, the force on the radius arm tends to resist human forces…:slight_smile:

The lay-out with inboard brakes may have a bearing on ‘our’ play - ‘modern’ outboard disks may limit wheel ‘wobble’…?

xj6 85 Sov Europe (UK/NZ)

(tony) #130

imo, you should not attempt to remove the oil seal seating ring or water deflector, as there should be neglible wear, the seating ring will probably need to be cut & split off, the water deflector is known to be tricky to re-attach without risk of later detachment and rattling, and a new seating ring is an interference press fit…and surprisingly expensive from memory

that shaft pitting looks a wee bit concerning

(Mark Lee (Pay Pal Patron)) #131


Well here’s a video of the carrier - it would appear it’s sustained a bit of trauma too. Is it garbage? I’ve considered adding a bit of aluminum to the casting with a couple of weld beads, I have serious reservations about that idea. because of, well, adding metal to this is gonna be a hot mess. Nearly 50 years of exposure to the elements as well as grease. Then there’s warping, which could be mitigated by pressing in a race to hold things in place and act as a heat sync. The biggest concern is weakening the integrity of the aluminum, unlike steal, the weld is the weakest part of the join.

Where the race is pressed in, it appears to be fine, so open to your thoughts.

(tony) #132

its my understanding, if the bearing race spun, the item is considered to need replacing, however, maybe a little loctite would overcome that concern.

the rat-nibbled appearance of the fulcrum shaft area, never seen that

(Mark Lee (Pay Pal Patron)) #133

Rat nibbles.

Me either, it looks like a bad casting, combined with years of driving. The holes look like porosity

Sent from my BlackBerry 10 smartphone on the Verizon Wireless 4G LTE network.

(Frank Andersen) #134

With no visible cracks and the outer tracks had to be pressed in with force(?), Mark - I see nothing very alarming on the hub carrier itself…

The striations at the fulcrum shaft seems like the carrier contacted the road at one stage - possibly on a deeply rutted farm road? It’s definitely no ordinary wear - and would have been a reject if it was a casting fault…

I do notice a bit of an indent in that area - it is not perfectly round. If it poses no problems in fitting the fulcrum shaft and bearings - I don’t think it warrants any action. Welding anything on the hub carrier is discouraged - for the reasons you mention…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

(Mark Lee (Pay Pal Patron)) #135

Status update:
I’ve reviewing the wear of the inner fulcrum shaft bearings wondering if they are resuable or not. the races definitely have a wear pattern to them. but after sitting in a bit of PB Blaster for several days, the crunchiness has gone away.

However, the wear pattern in the centre races is detectable through the long shaft connecting the inner fulcrum arm to the diff. I’ve got a video where I mind-numbingly ramble about bearings. Like I know what I’m talking about. I haven’t gotten the edit done yet. This takes a huge amount of time for somebody like me who’s OCD and want’s the end product to be worthy of a Golden Globe.

Anyway, I’ll keep you posted when I get new content on youtube.

Thanx for following this thread

Oh, yeah. Questions regarding the fulcrum to carrier sealing. Factory is a felt seal. I thought I read someplace in this thread that there was a "new style" replacement aka not felt? I think it was Kirby who spouted off a national seal number - but I can't find it. If anyone knows, please share. Also, spacing between the fulcrum and carrier where it all fits back together. This one has a considerable amount of sideways slop. Like about a 1/16 of an inch. I can't imagine that shims are used to take up the slop because the shims would disintegrate in now time at all being exposed to road dirt and weather.

I didn’t see anything in the Green Bible. Does anybody have clue as to what I’m on about? or better yet the acceptable tolerance between the carrier and the fulcrum.

Thank you as always

(Robin O'Connor) #136

Different beast but the same set up. I have just removed the hub carrier from my XJR and it was a tight fit between the lower arm ears whithout shims, my ‘S’ type I believe will have shims

(Mark Lee (Pay Pal Patron)) #137

Thank you, but I was talking about the outer fulcrum tolerance between the fulcrum ears (for lack of what knowing the actural term) and the carrier & hub assembly. there’s quite a bit of slop. I did have a bright moment by leaving the other side intact as a reference. and I don’t see any shim there but there’s quite a bit of greasy felt bulging out saturated with oil or old grease. My point is I didn’t see any shims - but tat doesn’t mean there aren’t any.

but I just looked at the parts guide, and sure enough there’s sims in there. .007 and 003. which aren’t going to be thick enough to keep it from sliding on the fulcrum shaft the rod that’s threaded on both ends.

Now I’m wondering if the carrier needs to be replaced too. I’d put a video up, but I’m tired, I’ve had an emotional day with my daughter - So being “lively on video just isn’t in the cards today”

Tomorrow’s a new day with new hopes.

(Mark Lee (Pay Pal Patron)) #138

I’ve got a couple new videos posted.
removing the fulcrum arm
removing the emergency brake
the next video is removing the caliper assembly
then painting stuff
I have a tips and tricks video in the works too.
I had no idea how much time it takes putting these together. Partly because I’m learning the software at the same time. I should know better. Learning the software + Providing a product = deadline failure.


Tell me what you think in the comments. Be honest. If they suck then tell me why? So I can improve. I know the fulcrum one sucks, and the e brake video I kept on forgetting about the camera… It’s a learning process.


(Mark Lee (Pay Pal Patron)) #139

yeah, I think I am interested. PM me with your address and I’ll send a shipping tag. how much does it weigh? and how much of it is in good shape

I see a couple of goodies in the box that I will be needing. :slight_smile:

(JAY COOLE) #140

sending pm your way now

(Mark Lee (Pay Pal Patron)) #141

I received the new parts for the IRS hub & fulcrum arm. Even though I purchased a used carrier I’m still considering using the hold one that has been the topic of discussion and a couple of videos.
That being said, I set the fulcrum and hub on the table with the carrier between the two mounting points and did some measuring.
The total space between the outside fulcrum and the carrier is .044 inches the big (outer) shims total .025 and the total of the smaller ones that go between the tube inside the carrier between the two tapered bearings is a total of .020.

I"m assuming I’m not supposed to count the inner shims because those shims provide are for the fulcrum bolt / tube between the tapered bearings. So, that leaves the outer big shims
.044 - total space between the outer fulcrum (fork) and the hub where it will mount
.025 - total thickness of all 4 shims
.0019 - is the difference between the shims and the space.
according to the book, (I think, if I understand) that leaves .0009 of weeble wooble left.

I suppose a more accurate way is to figure the preload after the it’s all put back together. I wanted to have an idea of whether or not to use the carrier in question, or the used one that I bought, that look like new, and could probably just be put in place - and not disassembled.

I’m not sure what to do.

So the question is this.
The di