22 replies to this topic

[natcamp10]

Hi all
Looking at upgrading my front brake set up on the lj
I’ve heard xj6 4 pot calipers are a direct swap , is this true or do I need to change discs to commodore ? If so am I able retain my 13” wheel s ?
The vented disc would be a massive Improvement , anyone out there done this that could give me a run down
Thanks
Nath

[Rockoz]

Havent heard of that conversion before.

Given that there are likely to be easier ways to get better brakes I would wonder if it was worth the effort.

 

The easiest way to check is to have the calipers handy to you.

The mounting holes on the calipers would be the first thing to check.

 

But remember that the mounting holes are done on a circumference measurement as well as a distance between holes.

You might have the same distance between the holes, but if it isnt the right distance from axle centreline, the pads may not be in good contact.

 

Perhaps find out as much as you can from a brake website. 

Find the diameter of the xj6 discs for starters. The disc you use also needs to be around the same thickness as the original, or you may find you will get piston locking problems,

 

 

Have you got the calipers already?

 

Cheers

 

Rob

[natcamp10]

Hi ya
Yeah I got 1 caliper to start the mock up
You mentioned piston lock and it’s got me thinking
I did the front brakes up a couple of years ago where I changed The calipers to Twin piston gtr Girlock type but I wanted to run the thicker xu1 discs so I had to ad a small spacer between the caliper halves to fit the bigger discs , Ive had nothing but issues with this, the brakes are only good for a couple of good applications then the brake fade starts , also lh locks up really easy , I’ve done everything I can think of besides replacing the caliper again , I actually think the issue is in the rh side ,I stumbled across a post here for the xj6 caliper conversation but it went into using rx7 4 pot calipers in the end but it started with someone commenting on the use of xj6 caliper as a straight swap the post was never finished , I just so happen to stumble across One so I grab it to look into it , I know there is a lot of alternative Holden options but I really wanted to retain the 13 inch wheels ive tried everything with this set up , rebuilt calipers , new slotted discs , new brake lines , 8 inch booster and 1 inch master cylinder all brand new , lines have been check for any restriction , I converted originally from a remote booster v44 type with 1 piston pbr calipers ,the car was always on the road during the conversation it was done over a week , I was going to get the disc machined and try a new set of pads but to be honest I’ve got the shits with this setup atm
Also after a long drive around 50 km the lh starts to smell like it’s dragging , I’ve checked this many times and come up with nothing. Flexible lines are new as well no abnormal wear , I’ve gone through the setup on the boaster and Master cylinder many times ,if it was a setup issues there why is only 1 caliper giving me grief
A little frustrating with the it atm the amount of money I’ve spent in that area and if I’m up for changing disc and getting caliper a rebuilt again I would rather invest into a vented disc set up But it looks like I won’t be able retain my 13inch stud pattern , iv also heard there is a Volvo conversion as well

Sorry rh starts to drag not the lh

[jd lj]

The Volvo calipers with BMW ventilated discs is a good set up and still uses 13" wheels.

[natcamp10]

Hey Jd
Can you remember the models so I can see if I can get the bits
I’m really open to any options here I just thought the 4 pot jaguar setup was interesting when I seen it

[dattoman]

We used to fit HZJ75 Landcruiser calipers onto HQ's with the vented disc

 

Have used the Jag caliper on Commodore discs before (328mm  with bridge spacers) but this was on a Jag

 

Haven't seen the Jag caliper on a Torana before

Its a heavy hunk of cast iron ... thats its major drawback

[natcamp10]

Hey all
So yup xj6 calipers bolt straight up
Cannot fit the 13 inch wheels over the big buggers , hack the crap out it with a grinder , got real close to making it work but the calipers are tad to long , the only way I came up with making this work would be using commodore disc vb or vh and changing to 14 inch rims at the front , if any one has some more info in regards to to the bmw and Volvo setup with vented disc that would be much appreciated, jd lj put me onto a great start that was done onto the red rocket get in the nc race series and is great read but unfortunately not enough detail in it to tackle it at this point
All I’ve got so far is Volvo 144 calipers not sure on what bmw vented disc where used and it looks like there was modified stub axles and wheel bearings fitted
There was a fellow by the name of Keith Croft who did the mod for the fellow and did all the machining etc
Thanks all in advance for any input
Nathan

[yel327]

Probably a stupid question as the answer if probably obvious, but why the desire to keep 13” rims?

Did XU1 have a high speed H rated tyre like GTS327/350? I’m pretty sure that I have to run 15” tyres on my GTS327 to be legal as I can’t buy 130mph+ tyres in 14”. Very few V rated 14” tyres if any available outside repro crossplies.

[RallyRed]

Hi mate,

My green track car has the BMW vented / Volvo twin spot conversion.

It is a well used mod and is a fair bit superior to the factory setup.

13" wheel friendly.

I recently replaced both front discs....see pic.

I get that sort of stuff from Darren and Bruce Stewart at Performance Road & Race Part in Sydney.

They can supply them heat treated if you wish.

Regards

Col  20191010_170039.jpg   172.95K   4 downloads

[natcamp10]

Hey mate
Thanks for the reply , are those rotors bolting straight up to the standard stub axles ?
Regards
Nathan

[RallyRed]

mate . to honest I dont know.

I understand these track cars run a HK? front upright/spindle ( to raise the spindle centreline)....if that spindle is same as Torana , then yes?  

Someone may chime in with info..

[claysummers]

Same spindle and bearings FE to WB, LC to UC.


Sent from my iPad using Tapatalk

[claysummers]

Mates setup running HG spindle and disc with 75 land cruiser 4 pot calipers. Obviously 14” rims required with this setup but maybe an option to run the same calipers on Torana stubs. Some photos of the latest upgrades
https://r.tapatalk.c...link_source=app


Sent from my iPad using Tapatalk

[natcamp10]

Hey clay
Really want to retain the 13in wheels
But looks great tho
Nathan

[natcamp10]

Hi all
So I found some Volvo 240 series 4 pot ,haven’t purchased them yet.. they have mount hole centres of 3 inch where as standard mount holes are 3/1/2 inches , can anyone confirm what studs do I use or possible a bracket to adapt
The fellow who I’m looking at purchasing these off of says these are the ones people use to put on The Tories
Regards
Nathan

[dattoman]

In the Volvo range there's ATE and Girling calipers

Different piston sizes avail in each

Also solid or vented discs varieties

I prefer Girling vented which take the larger DB549 pad shape

 

They also run 2 fluid inlet holes

So you either need to drill passages to run a single inlet or run 2 hoses in

I can send you pics of the drill requirements if needed

 

From memory we plugged the mount holes and redrilled them to suit the stub

 

 

[natcamp10]

Hi Mate
Yup these are the girling 4 pot calipers with two inlet ports ,
Are you able post those pics please, that would be awesome
Regards
Nathan

[dattoman]

These may help

 

 1.JPG   24.37K   2 downloads

 2.jpg   38.27K   1 downloads

 3.jpg   19.35K   1 downloads

 inlets.jpg   35.42K   1 downloads

 mounts.jpg   34.69K   2 downloads

 outer.jpg   31.56K   1 downloads

 

[UCSLE]

i looked into using the Volvo / BMW set up for one of my cars , there seams to be a lot of work to fit them

 

the rotors bolt up to the LJ type hub but the center bore of the rotor is too big 74mm compared to the LJs 72mm

 

 bmw.JPG   18.34K   2 downloads

 

with the caliper it looks like the yanks got single inlet ports on there late Volvo 240 91-93 abs calipers ?

they could be a better alternate but cant find much info on them comparing them to the twin ports 

 

shop around but here is a example https://www.ebay.com...8ff9d88e5|iid:1

 

 91-93caliper.JPG   26.12K   2 downloads

[natcamp10]

Hey guys
So I’m picking the calipers up today, dottman is there somewhere in wa where I can take these to get modified , sort of assuming to get a drill in there won’t be easy
Also for the discs might be able to get a small spacer turned up to change froM 74 back to 72
Regards
Nathan

[dattoman]

Perth Brake Parts used to drill them

Fairly common thing years ago

[natcamp10]

So I got my calipers and planning the first stage , will post pics , got me self a gas burner for pre heat and some Nickel rods , I’m going to arc weld the mount holes up and post heat down again , before I go ahead what would be the preferred method here gas , arc or tig , sort of ruled out mig already , am I on the right track ?
Nath

[RallyRed]

I know you are in W.A mate...but the easy way is to get onto Keith Croft...he sells the complete deal as a bolt on thing.

I guess the postage wouldnt be pretty.

FYI anyway.

Good luck either way.