New Build suspension and upright torquing

[Dan Marsh]

I am happily stuck into day 3 of my build and have passed the dreaded top damper mounting bolt (though I forgot the plain washer next to the sprung one as the manual mentions it only after you've fought the bolt in!).

 

I am now wondering how you get access to torque up said bolt and also torque the top wishbone ball joint to the upright? Am I missing a trick, do you have tiny wrenches or is it a bit of an educated estimation?

 

Cheers

 

DM

[bluenose]

Dan

 

You only torque up the suspension when the car is on its wheels. You can get to most of the bolts but you may need some crows foot wrenches to attach to your torque wrench like these

 

Nick

 

Lava Orange Caterham Blackbird

 

[Dan Marsh]

Thats interesting because I've read that elsewhere on here, but the build manual has the same torque values during the build as it does on the page of final checks before PBC etc. It tells you to do it as you go along?? Maybe I should make a call to CC to see what they suggest...

[Rattie]

It's worth giving CC Aftersales a ring and asking for Sean Cummerson. He's the font of pretty much all build knowledge.

As for torquing suspension bolts, you only really need to put the wishbones into the right sort of ball park position before torquing the main bolts. To do this, wait until you have the uprights in, then hold the assembly so that the rear tube of the bottom wishbone is horizontal. That way you won't be preloading the bushes.

 

To torque the top bolt (Allen), we used a ball ended key and a convenient part from our socket set that's supposed to form part of a t-bar 1/2" drive, but has a 3/8" hole in the top and a through hole in the side. I'll take a pic and post it on flickr. Worked great.

 

Martyn

^{_{R300GRR happy in Dartford until the Thursday after passing IVA retest!!!}}

[Dan Marsh]

Thanks. I've emailed Sean re some missing bits and have sent one about the torquing to Chris (tech man apparently). We'll see what they have to say tomorrow. Silly question, but "preloading the bushes" means...?

[Rattie]

First off, my tooling for the top bolt.

 

Once you torque the bolts that go through these metalastic (metal and cast rubber) bushes, that sets the "home" position of that bush and any deflection from that position causes a restoring torque in the bush. Put simply it want to stay in that position, it's a rotary spring of sorts. If the home position isn't where the suspension elements fall at rest, then you are storing up energy in the rubber, which over time causes the rubber to fatigue faster.

 

So you try to avoid that by torquing the bolts up while the wishbones are in the position they will be in most of the time. The simplest way to do that is with the car on the ground, but it's easier before the damper and other bits are installed.

 

Martyn

^{_{R300GRR happy in Dartford until the Thursday after passing IVA retest!!!}}

[CageyH]

Is the bolt through the bush an interference fit then?

[Rattie]

You lost me.

It's the mounting flanges in compression that lock the inner sleeve of the bush, if that helps.

 

Martyn

^{_{R300GRR happy in Dartford until the Thursday after passing IVA retest!!!}}

[Dan Marsh]

Thanks Rattie. GoI undestand now and I can see why the manual tells you to torque the nuts when the wishbones are horizontal and why it is then more awkward to make everything else fit together. I'm sure it wouldn't be in the manual if it was wrong...maybe

[spiderlane]

I'm sure it wouldn't be in the manual if it was wrong...maybe

 

Heh, don't you believe it :)

[Dan Marsh]

CC say do it after weighting the car. So i've loosened it all off again, made a start on the ARB and then broke a ball (actually the one that was in its cup nicely as I tried to force the other in). And thats the end of that until CC can send me new stuff when Sean is back next week. ☹️

[spiderlane]

Dan - I broke a ball too (in identical circumstances) and bought 2 (one spare) from CC which arrived this morning.

 

I'm hoping to get the ARB in tonight and if I do I'll gladly send you the spare one in the post (assuming I don't need it) - that way it might arrive at the weekend so you can get on. Blatmail me your address if you're interested.

 

 

 

Edited by - spiderlane on 18 Mar 2010 15:29:07

[spiderlane]

Fitted my new balls and just went to install the front ARB.

 

It seems to be way too short - when one ball is only about 5mm into the cup the other one isn't even starting to go inside - and this is with the bar brackets tight on the front of the car. i.e. there's no more forward space to go.

 

With the brackets in place, each ball just has it's equator at the front rim of the cup. Here are some pics

Overhead

Left

Right

 

Could I have the wrong size ARB? I notice a number of them on the parts site. I have a widetrack SV so perhaps I've got an S3 bar or non widetrack. Any ideas?

 

ETA - Pics.

 

Edited by - spiderlane on 18 Mar 2010 18:44:35