Instructions to replace a REx yourself?

[james0157]

Hi there, I have a BMW i3 with a non functioning REx, diagnosed. I'm on a great big budget, I have tools including the ability to raise the car up myself, and I have access to a nice dry workshop. What I'm looking for are instructions. I've managed to isolate the HV battery, get to the REx after removing the rear bumper, exhaust and airbox, however I'd like to know how to get to all the bolts needed to remove the REx and lower it down and out of the vehicle. Tragically there appears to be no Haynes manual for the i3 REx nor can i find a step by step guide unless anyone knows of one?

Thanks in advance!

 

[EvanstonI3]

There is a guy in the USA who recently replaced his REX by himself and posted about it in a BMW i3 USA group (it is only for USA-market i3). He seems willing to help others who want to do the same thing. Since you seem to have FB access from another post, this is his PROFILE: https://www.facebook.com/tom.otto.2024/ I would suggest try Messaging him and see what he says. I have no idea if he is in this Forum because no one posts under their Real Name and I don't recall seeing him post this info here.

 

[james0157]

There is a guy in the USA who recently replaced his REX by himself and posted about it in a BMW i3 USA group (it is only for USA-market i3). He seems willing to help others who want to do the same thing. Since you seem to have FB access from another post, this is his PROFILE: https://www.facebook.com/tom.otto.2024/ I would suggest try Messaging him and see what he says. I have no idea if he is in this Forum because no one posts under their Real Name and I don't recall seeing him post this info here.

Thank you very much for your suggestion, he's provided a wealth of resources and advice. Midway through doing it now and feeling so much more confident!

 

[3rigel]

I've just removed a rex engine from a car I'm breaking, front end damage. I removed the Rex and electric motor together. If you want some tips, remove the drive shafts early doors and the HV cable that runs down the UK Passanger side near the motor when you can. It may seem a small cable in the grand scheme of things but when things are this tight every inch counts. If you have a couple of ramps getting the back end on those will help give clearance later on too. Best of luck!

 

[kd7iwp]

I've just removed a rex engine from a car I'm breaking, front end damage. I removed the Rex and electric motor together. If you want some tips, remove the drive shafts early doors and the HV cable that runs down the UK Passanger side near the motor when you can. It may seem a small cable in the grand scheme of things but when things are this tight every inch counts. If you have a couple of ramps getting the back end on those will help give clearance later on too. Best of luck!

Can you explain to me what "early doors" are?

 

[3rigel]

Can you explain to me what "early doors" are?

Near the beginning of the task that's all.

 

[james0157]

I've just removed a rex engine from a car I'm breaking, front end damage. I removed the Rex and electric motor together. If you want some tips, remove the drive shafts early doors and the HV cable that runs down the UK Passanger side near the motor when you can. It may seem a small cable in the grand scheme of things but when things are this tight every inch counts. If you have a couple of ramps getting the back end on those will help give clearance later on too. Best of luck yes

That's great thanks, I have a guide to follow now but annoyingly it starts from after the axles are removed.
I've never done any work on axles before and still a tad uncertain on steps to remove them, throughout the whole job it's the one thing I'm finding the most vexxing. Am I right in thinking the steps to remove the trans axles are:

1. Remove axle bolts from middle of rear wheel hubs (obvs after removing wheels!)
2. Remove and hang brake calipers
3. Potentially remove the control arms from the backs of the hubs
4. Pull the axles out horizontally through the wheel arches

Do I need to do anything with where the axles meet in the middle or is there an easier way, and are any axle specialist tools needed?

 

[kd7iwp]

Does this help?

Right side:



Left side:

 

[james0157]

Like you wouldn't imagine, thank you so much!

 

[TedStriker]

Like you wouldn't imagine, thank you so much!

Remember when retightening suspension arm bolts, the suspension should be in 'normal' position, ie the same position as when the car is at rest on its wheels. If you tighten them when the suspension is hanging you'll put huge stress on the rubber bushes. As for drive shafts, I replaced one on mine and there was nothing unusual about it. I suppose the important bit is to make sure the slotted flange on the shaft engages properly with the hub as mentioned on the last part of the guide above. It's not splined like many cars are.