19 replies to this topic

[yel327]

I wish to upgrade my banjo diff to accommodate HQ drum brakes. This would mean engineering the axel from Torana to HQ stud pattern. Since the HQ stud pattern is larger will the plate that the wheel bolts attach to have sufficient space or will it also need to be reengineered. My question is can it be done or is there an axel that can be used.

I have done research into upgrading the diff such as 9in or Borg Warner conversions but these are outside my budget.

Any comments or suggestions are welcomed. Also any recommendations on who can do this work in the Perth area.

Thanks
John

John

You don't have to go to HQ stud pattern just to get HQ rear drums. You can use HK-HG drums on LH-UC diff with no modifications. Apart from wheel cylinder bore variations HK-HG are identical rear brakes to HQ-WB except for the stud pattern the drum is pressed for. You can even use HQ brake assemblies with HK-HG drums. Torana handbrake cables go straight in too.

This is academic of course if you are changing to HQ-WB front brakes then you'll want the 4.75" stud pattern on the back too. If that is the case I have seen axles redrilled before but I cannot vouch for their strength. L34 axles had bigger flanges (HQ) on them, but A9X and HZ/WB disc brake axles have a much smaller flange diameter (with HQ pattern studs) that is not that different to the Torana flange. A diff specialist will be able to help you more.

Byron

[TerrA LX]

I can not think of one good reason spending money upgrading to HQ drum brakes.

[ls2lxhatch]

John wants to fit wheels with HQ stud pattern but does not want to spend money on disc brakes for the rear. The front will be HQ discs machined to suit Torana callipers.

[Struggler]

I have had the banjo axles welded and redrilled a few times. Any machine shop can do it for you, take your drums along too to get them drilled as well. I wouldn't bother fitting the HQ backing plates and internals though, the rears will lock up. Just leave the Torana brakes and redrill the drums.

JMHO

[yel327]

I don't understand why you wouldn't change to HQ-WB brakes if you fitted HQ front rotors (I do understand why you wouldn't bother if you had redrilled LH-UC discs). I've done this a few times before and never once had rear brakes lock up on me. In fact the brakes were better on road than when I later fitted an A9X diff. I would have thought it would make sense to do it, especially since you are copying what Holden did with the L34. If the brakes are locking up something isn't done right, or am I missing something?

[ReplicarSLR]

1ARC - Speak to Phil at Final Drive in O'Connor 9314 6811 or WA Diff Centre also in O'Connor 9314 2303

[TerrA LX]

Ended up fitting disc break nine inch have never looked back!

And what axles are fitted to this diff?

[yel327]

I've tried doing this and the problem is getting the axles. I when to several diff joints and have now had two set of HQ axles shortened and re-splined and hardened to suit Tory length. Works ok for normal driving but first time i went to give it a bit both sets of axles snapped at the point they were re-splined at after twisting. $800 down drain. Ended up fitting disc break nine inch have never looked back!

I told the same story on another thread. This is exactly what I had happen to me - ie splines twisted and snapped on shotened HQ-HZ banjo axles.
I didn't use a 9" though in the end. I got some A9X axles and shortened a Salisbury to suit. Moved the top mounts and fitted HZ disc brakes. Never broke that.

[Struggler]

I don't know why anyone would want to respline a banjo axle. The only Holden axles to respline are 1 Tonner ones.

Why aren't you just getting the LX axles stud pattern changed ? The HQ brakes will still bolt on to the LX diff if this is what you want to do.

When I fitted HQ brakes front and rear I suffered rear wheel lock up at the engineers braking test. To fix it I used HT/G/K wheel cylinders. After that I just left the LX rear brakes and changed the stud pattern and they always passed the brake test.

This is just my experience. Feel free to do what you wish.

[yel327]

I have heard nothing by negatives towards the re-splining of axels. I have been told that the WB axels should be used when re-splining axels and that there is no need to re-heat treat the WB axels. If the car is not used for racing, draging, roll backs, burn outs and placing other abnormal forces on the diff is a re-spined axel sufficient.

Is re-splining done only in fine spline? Is this not the same as the L34.

Is there anyone out there that has re-splined fine axels and has had no problems.

Thanks John

John

WB 6cyl axles (except tonner) are exactly the same as HQ-HZ banjo axles (although HQ/J are coarse spline). WB V8 axles (except tonner) are the same as HQ-HZ. WB tonner axles are the same as HQ-HZ. So whoever told you that is probably telling you porkys, although there may be some merit in it if they are talking about 1-tonner axles. I'm not 100% sure but I have heard they are heat treated and there is enough meat in them to respline to either 28 spline in LJ length or 23 spline in LH length. I'd be getting proffessional opinion before contemplating it though.
I do remember boing told that Ford drum brake axles are heat treated prior to splines being cut so the treatement is deep enough to allow cutting and resplining, whereas Holden axles have the splines rolled and hence the treatment isn't deep enough to allow new spline cutting. But tonner axles may be different.

[MRLXSS]

I have a 9" at the rear end of my Torry, and i am using bigger HZ Drums now. I also upgrade the front to HZ as well. The car stops So much better than it did before! The rears use to lock up with the Torana brakes along my dirt road. But now with the bigger drums they dont! As long as you dont have wheels that show off the ugly rear drums, i dont see the point of getting discs for the rear on a Streeter/part time fun car

Edited by MRLXSS, 29 July 2008 - 09:07 AM.

[Toranamat69]

I'd be getting proffessional opinion before contemplating it though.

And anyone who recommends resplining an axle doesn't fall into that category.