MK1a to B-spec ARBS, Struts etc

[Lauren]

I've been busy on my MK1a this weekend trying to get everything done in time before it goes into the bodyshop.

As i had a full set of working brakes and struts with konis and fensport springs i figured that i might as well put them on my early car.

The front suspension was pretty easy, i just swopped the whole lot including lower arms and simply unbolted the 'castor' arms (can't think of a good name for them!).

I simply drilled a fourth hole to accomodate the late top mounts.

I also put the front ARB on as it was slightly bigger. I did notice that the droplinks don't seem to sit straight anymore, but comparing the bars they seem the same in size. I'll have to have another look at it later.

On the rears i just swopped the struts over and the brakes. On the early cars the rear hub bolts are 17mm but on the late cars they are 19mm.

As i was retaining the early hubs i bolted them up to the struts and noticed there is a bit of play as the hole is bigger in the strut. Mark noticed it and mentioned that we had a problem. Actually it was a bit of a result, as i reckon there's another degree of negative camber to be had so we maxed out the camber then held in hub whilst doing up the top mount and gained a bit more neg camber or so i think anyway. Its a little naughty but the bolts are done up to 160lb/ft so they aren't going to move.

Only slight hiccup came when i tried to put the later ARB and noticed the mounting holes are some 2" out! The only thing is is that where they bolt to is a chassis rail by the looks of it so i guess i'll have to use a couple of long nuts and bolts to be able to fit it. Question is the best way to simply drill upwards where you want the mounting bolts to go until you come through into the boot floor and do it that way. Am guessin the bolts are going to need to 4-5" or so?

I guess this is one for Paul Woods as i know he has done stuff before on rear ARBs. Does anyone have an idea of the size of the MK2 tubby bar?

I figure that if i'm gong to have to drill some holes i might as well upgrade it at the same time.

[crazylegs]

could you take a pic of the rear arb for me.i am not sure what you mean when you say its out.as i will probably going down this road it would help.ta in advance .

[PW@Woodsport]

hi lauren,the mk2 tubby bar is 19mm....i had no idea the late spec bar sat 2 inches further back so thats new info.

Id forgot about the late hub bolts being bigger too,i had to do a little modifying as well,but if i remember right when i added the spacer plates from the early car this made things right.There was too much of a gap between the late shocker mounting point and the hub to just risk nipping it up tight.

On fitting the tubby bar heres what i did....the bar sits on the chassis legs,which have captive nuts inside the chassis.Now the tubby bar needs to sit around 2 inches further back on the chassis legs.If you take the rear wheels off you will see you get good access to the sides of the chassis legs where the ARB is mounted.I cut a small U shaped flap in the side of the chassis leg right above where i wanted the new ARB position to be.This flap was only 2 inch square.Bend the flap up and you get enough access inside the chassis leg to be able to get a MIG welder tip in.I mounted the ARB where it needed to be and drilled the new holes for it.I then removed the bar and fastened up nuts and bolts into the holes putting the nuts on inside the chassis via the flap hole.I MIG'd the nuts captively onto the chassis and then while the chassis was open i gave it a damn good waxoyling.I welded the flap shut and seam sealed it...thats pretty much it.

The tubby rear bar is well worth fitting,a great upgrade...well at least for a 3s-gte powered car,no idea how it will act with a 4a,should be good.

[Lauren]

Hi Paul,

19mm is going to be bigger than the front! I think i'm going to stick with the late spec 12mm bar, for me 16mm would be the absolute maximum as I don't think it would do the handling much good going to that size.

The rear struts on my car didn't seem too much different width wise with the later strut. From what i could see all the movement was in the bolt holes.


Kev, if you offer a late spec arb up with the drop links vertical you can see that the holes are a good 2" inches out. You possibly could at a push use one of the mounting bolts, but due to the shape of the bar ( it is markedly different from the early arb) it has to go further back too.

Mark did take some pics i'll try and get him to sort it when he comes in tonight.

[PW@Woodsport]

yep the 19mm bar is used with the 3s-gte conversions because thats whats used on the mk2 tubby,and it works incredibly well,you might be right about it being overkill on a stock mk1 though,would be interesting to find out .

[Lauren]

yep the 19mm bar is used with the 3s-gte conversions because thats whats used on the mk2 tubby,and it works incredibly well,you might be right about it being overkill on a stock mk1 though,would be interesting to find out .

I think firstly i'm going to do the geo and then try it with the stock rear ARB and see what i think. But it will be a month or two before i can get it on the track and see what its really like.

If i think it needs something more then i may just give it a go. Its just i heard a report of one of the US guys who played around with ARBs saying that a 19mm on his SC didn't work too well.

We'll see.

Just want to get my car on the road now, its going to be another month at least!

[crazylegs]

i had a look today at my arb and jinxys i dont see that the mounting points are any different.am i missing the point ? i know the bars are totally different but thats why the drop links are a different length. i only had a quick look ,is it the mountings with the bushes you are talking about or the position of the drop links?

[Lauren]

i had a look today at my arb and jinxys i dont see that the mounting points are any different.am i missing the point ? i know the bars are totally different but thats why the drop links are a different length. i only had a quick look ,is it the mountings with the bushes you are talking about or the position of the drop links?

It wasn't the drop links that was the prob Kev, it was that the bar needed to sit a lot further back (well a good 2" or so) where it bolts onto the chassis. It will be obvious when you try and bolt up a late spec bar. The droplinks can't go forward as they will simply hit the strut. The 'arms' (ie the two ends of the bar that curve round to meet the drop links) are a fair bit longer which i guess is why you can't use the same bush mounting points (i hope this makes sense!).

I had late struts with the late drop links so I don't think its an issue with the drop links. You can also see where there is a kink at either end of the straight part of the bar where it cannot fit in the same position as the MK1a bar. I did fiddle around but there was no way it would go tbh.

I'm just getting Mark to sort a pic of the two bars together as you can see the difference in the length of the ends.

[Lauren]

Just to add to this, i've used the original rear ARB with late rear struts that of course have the late droplinks which bolted up perfectly.

Here's a pic of the two bars, look at the difference in length of the reach:

[Lauren]

Just to add to this, i've used the original rear ARB with late rear struts that of course have the late droplinks which bolted up perfectly.

Here's a pic of the two bars, look at the difference in length of the reach:

So you can see that the later bigger bar has to mount further back

[crazylegs]

thanks i`m with you now.i`ll have to think on this one.

[MegatronUK]

Jeez, that early ARB is like coat hanger wire!