CAB "30 minute window" question

[Dsun]

Hey guys,

So my question is, what is the worst case secnario that will happen if I cannot get the car on the wheels within this 30 minutes?

It only applies once the CAB is put back on the CA right? As for lube, should I dilute Dawn with water or should I just put Dawn straight on the CA and inside the CAB hole?

Are there special tools I can buy to help me put the CAB back on the CA?

Thanks!

[SmokeE30]

are you using oem rubber or poly bushings, polly i used silicone lube to slide them on the control arm and ditn have the car back on its wheels for weeks.

[Dsun]

oem rubber, m3 offset

[E30_fiend]

As long as you have everything ready to go, its a very fast install. Just use dish soap for the rubber bushings. Once you get them started, start rocking the bracket back and forth and pull at the same time. They will slowly walk onto the control arm. Then once they are lined up with the bolt holes on the frame, get the bolts started and torque them down. If the bushings arent on as far as they should be, once you turn the wheels a few times, they will seat right where they are supposed to be.


Taylor

[jeffnhiscars]

BMW says 30 minutes because they use a specific lube that is designed to dry in about that amount of time since you have a tech working flat rate. I use electricians "wire pulling" lube which is also water based but is heavier so in theory it will have a longer working time than say dish soap.

The purpose in getting the car on the ground asap is that the CAB's will "bite" the CA once the lube is dried and you do not want that to happen without normal loading on the suspension. Otherwise, you will preload your CAB which will significantly shorten its life.

There are some good ways to get the CAB on as mentioned. I've used brute force, a puller & even a little heat on the CA. What worked best for me was to install the inner ball joint, swivel the CA so you can get the CAB on by whatever method. Then pivot it to install the lollipop & outer ball joint, install the wheel then drop that side of the car. Should not take more than 10-15 minutes at that point.

I would also STRONGLY encourage you to get an M12x1.5 tap to chase the threads where the lollipops bolt to the chassis. These threads do get galled and snapping one of these off is not pretty. The tap cost me $5 at Grainger.

[Dsun]

thnx for the tips, doesnt seem that bad now

what do you mean by "chase" the threads? does that mean retap the threads or does the tap "clean" the threads?

[Van Westervelt]

You arent using the tap to cut new threads, just to chase the old ones. It isnt changing anything, its merely forcing any obstructions etc out and taking it closer to its original form as this is a common corrosion point.

A set like this isnt bad to have on hand... http://www.craftsman.com/craftsman-4...1&blockType=L1

This kit isnt quite a tap, moreso meant for cleaning and restoring.

[WhyNot]

maybe i'm overthinking this but i have an idea for when i do my cabs.
the cab inner dim are about 18mm and the control is 21mm
im almost sure that i can use a split shield anchor, ssab ,for a trick i have in mind.
the ssab is the when you drill into concrete.
you drill a 3/4 hole = approx 19 mm, drop in the ssab then screw the bolt in and it expands and holds the anchor
my plan is to put/jamb/hammer the ssab into the cab, then put the bolt in and expand the cab rubber to a little over the control arm, like 23 mm
then freeze the bushings. since they are frozen the rubber should hold this expanded size and be more solid like for any hammer blows
now the install should go super fast and super easy, im thinking
then put the car on the ground, bounce it up and down a few times and leave it alone.
then as it heats up the rubber will return to the original size and grab the control arm
ouch, i just burnt my fingers real bad on my crack pipe...more later

[110stx]

I suspect all this "30 minutes" BS from Bentley only applies to the concentric, webbed-rubber CABs.

With solid-rubber offset CABS, the control arms rotate easily within the CAB. There's no deflection of the rubber, twisting or deformation.

Meaning, the arm can assume whatever position it wants. No issue.

[jeffnhiscars]

You arent using the tap to cut new threads, just to chase the old ones. It isnt changing anything, its merely forcing any obstructions etc out and taking it closer to its original form as this is a common corrosion point.

Exactly. Its also a good idea to screw it in a bit then remove it when you start feeling resistance since crud can chew up your threads. When you are done you should just about be able to thread the bolt in by hand with a bit of never seize.

I suspect all this "30 minutes" BS from Bentley only applies to the concentric, webbed-rubber CABs.

With solid-rubber offset CABS, the control arms rotate easily within the CAB. There's no deflection of the rubber, twisting or deformation.

Meaning, the arm can assume whatever position it wants. No issue.

I don't think any of the rubber CAB's are intended to spin freely on the CA. The 30 minute suggestion is from BMW, not Bentley and I think all of the rubber OE CAB's are supposed to "bite"...even the offsets. How much it matters if they don't....meh !