Steel to Alloy Control Arm Swap

Highfield · Post by **Highfield** » Sun Oct 12, 2008 12:18 am

You know I don't embark on things without questions, so here goes.

I have managed to swap my steel arms for a set of 1977 alloy arms with the correct socket ARB mount. Come complete with hubs, e-brake and disc (will not be resued). The will be fully vapour blasted and satin black coated on the brake plate etc. and fitted with new bearings.

Before I take my steel arms to the new owner, he has let me keep both sets so I can swap over whichever parts I may need.

So, do I keep the stub axle from my steel arms and fit to the hub of the alloy arms ?

My steel arms have a stub axle with four bolt holes and two pins. The alloy arms have a stub axle with six bolt holes so my driveshaft would not bolt up.

The stub axle on the steel arms in approx 11cm diameter, whereas the alloy one is 10cm - will the steel arms stub axle fit inside the alloy arms ?

Do I need to machine off the three protrusions on the outside of the alloy hub around the big 32mm nut ?

I really need a definitive answer and help before I let anything go.

As ever, your help is very much appreciated.

Ian

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JWHillRacer wrote on DDK :-

You need -
2 Arms (obvious)
2 Hubs for alloy arms - they are the same ones from 74 to 89, but not easy to get hold of when you want them! (many thanks davidppp!)
Bushes etc - Thanks Nick, they worked a treat!
Longer bolts for connecting to the spring plates
Longer adjusting cams
New solid brake pipes
Possibly new handbrake back-plates, depending how easily the existing ones come off, and how rusty they are!
New Wheel bearings
If it's an original 72 car, the bolts for the suspension arms may well be fitted from the inside, so you will need to take the engine and gearbox out.
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impmad2000 · Post by **impmad2000** » Sun Oct 12, 2008 9:32 am

I've been looking at my drive shafts, seems I'm goin to have to mix some stuff up !
I have a 901 gearbox, with the large flanges, and Ally trailing arms (not that that's a problem ) with small flanges.

Here's a picture of the two drive shafts, note that the larger CV fits on the larger diamater shaft ! (also slightly shorter) and so I can't just switch the CV's and have one small and one large on the same shaft !! Perhaps I could get some of the larger drive flanges ??

This is a question I still have un answered.
I'm guessing that you have a 915 gearbox, same as the '77 car ? So my questions are slightly different. Perhaps swapping the drive shafts too ?
I'm guessing the drive flanges on the 915 gearbox probably changed at some point too !!
I'll be watching this thread carefully

Tim

impmad2000 · Post by **impmad2000** » Sun Oct 12, 2008 9:46 am

Following up on the electric 914 I've found this.

Looks like a relatively simple solution

davidppp · Post by **davidppp** » Sun Oct 12, 2008 9:53 am

hello both.

I think m,ost of us are abit reluctant to post ..

There are so many variations here, its a minefiled.

So here goes with exposing myself!

Ooo-er missus.

I believe the stub axlwes are interchangeable.

The drivesafts length is not an issue

And the hubcentric hub is OK as is..but not stock looking of course.

Kind regards
David

904GTS · Post by **904GTS** » Sun Oct 12, 2008 11:01 am

Adding to David's info if I remember correctly the outer flanges (with the wheel studs) are also different in depth so you need to keep them with the arms they came from otherwise the disc/caliper relationship will be wrong.

The larger CVs were used with the alloy arms through the 2.7 models then changed to the smaller six bolt type with the 3.0 Carrera at the same time changing the flange on the transmission to match. These CV's were used until the 3.2 models but the transmission flanges were changed again with the aluminium case 915 transmission. The driveshafts are all the same length but the splines are different for each CV type so you can't mix and match.

I use the smaller stub axles on my 904 replicas so could swap you for a pair of the larger type if you need them to go with the steel arms.

Regards

Barrie

Highfield · Post by **Highfield** » Sun Oct 12, 2008 1:52 pm

Thanks everyone.

Barrie, I will be keeping the outer flange with the wheel studs from the alloy arms.

Plan is to use the bigger CV joints and stub axle from the steel arms.

Concern is if the large flange will fit inside the "meatier" alloy hubs.

Have tried but no way I can Undo the big nut to remove stub axle.

Will take all four to Tuthills and get them to undo and also drift out the bearings.

Ian

impmad2000 · Post by **impmad2000** » Sun Oct 12, 2008 4:20 pm

Highfield wrote: Have tried but no way I can Undo the big nut to remove stub axle.

I carried the suspension arm to a local garage at lunch time and the mechanic popped the nut off in seconds using an air hammer.
Made life really easy

Highfield · Post by **Highfield** » Sun Oct 12, 2008 6:46 pm

Tim - I had a cup of tea and then got the bolts off the alloy hubs easily

I think I will do the same and drop them locally to remove the nuts.

I can then do comparison measures etc.

Ian

Highfield · Post by **Highfield** » Tue Oct 14, 2008 9:15 pm

Here is an update on the story so far, and currently going well

The above information was great, and I had a PM from JWhillracer. I rang JW and we talked through how he has 1972 driveshafts fitted to 1977 alloy arms, and they are just fine.

So, following Tim's advice, I popped along to Phantom Vehicles (yes, they do restore old Rolls Royce and Bentley, plus a Lamborghini and a Historic Raly Escort in the making) and it took them an hour to remove the nuts from the axles in the steel arms. They ended up using a torch to heat (oxy ?) and a huge vice, breaker bar and scaffold to restrain the lot from moving. Probably used Loctite and never off in 35 years.......but they are free now.

Once home, I simply swapped the inner stub axles between the steel and alloy arms. They are a close fit, but do not have any play, and the larger CV joint fits on OK as well.

The only problem is the nuts do not screw back on too freely, and I will buy new ones. I believe all the heating and forcing to undo may have affected them ?

Next question - is it a no brainer to fit new wheel bearings at this time ?

If so, how do I remove the old bearings, and is the outer hub with wheel studs easily removed ?

If needs be, Phantom Vehicles have a bearing press.

Ian

jwhillracer · Post by **jwhillracer** » Tue Oct 14, 2008 10:40 pm

Highfield wrote: Next question - is it a no brainer to fit new wheel bearings at this time ? - Yes!

If so, how do I remove the old bearings, and is the outer hub with wheel studs easily removed ? Bearings with press - hub can be drifted out with large hammer! (Didn't tell you I'm an Agricultural Engineer did I? )

Highfield · Post by **Highfield** » Sun Nov 02, 2008 8:07 pm

As an update, or lack of, the arms are at Phantom Vehicles awaiting the bearings to be pressed out.

The team had a stomach bug, and I was away on business so we have been delayed.

Hope to collect on Monday and get up to Redditch Shotblasting on Friday, so they can vapur blast and degrease.

Can or should the stub axle (not the splines) be powder coated or zinc plated ?

Ian

davidppp · Post by **davidppp** » Sun Nov 02, 2008 8:31 pm

Hello, Ian.

I like zinc passivate..
Make sure they are baked within 30 minutes mind..

Kind regards
David

Nick Moss · Post by **Nick Moss** » Mon Nov 03, 2008 8:12 am

I always leave the bearing shell in until after powder coating the arms. I would not powdercoat the stub axles, we always plate them but even that can add enough to make pushing the bearing on more difficult.

Highfield · Post by **Highfield** » Mon Nov 03, 2008 8:44 am

Confused - I now have the alloy arms so was just going to have them vapour cleaned and degreased - no powder coating on the arms ?

I know you do not see the stub axle, so if that is simply cleaned I may use as is.

I will be ordering new bearings for the rear and will get them pressed in by the local garage. I also have the ER bushings to fit, and am going to try out the Wevo E-Z Pins to bolt the arms back in without removing the transmission.

Ian

Nick Moss · Post by **Nick Moss** » Mon Nov 03, 2008 10:02 am

no powder coating on the arms ?

It's a matter of personal choice.