My Z4 Build... work in progress

[Z4inAZ]

This Z4 was in a minor front end fender bender when I bought it and was put on the backburner for awhile until earlier this year when I had time to finish it. Decided to do a little more than just fix it up, I had an idea in mind for the car and wanted to see it through to fruition. This is the first car I have really gone balls to the wall with

This is the oldest shot of the car I believe I have and it already had many new parts at this point, new headlights, bumper and fender liners



As she sits today, rear bumper showed up so went and got it fitted. Did not have to trim the support bar at all. Where are you SUPPOSED to trim the support bar? Right under the trunklid right? That sort of ledge area?






Door jambs, engine bay and trunk area are painted and final color is on the left... any guesses as to what it is? (its very dusty but the finish is actually quite nice in person)



Still have quite a lot left to do (any help/tips/advice is greatly appreciated)

- Convertible top isnt going down - solid light when you push the button, blinks when you arent pushing it. Top pops off windshield frame but doesnt retract. I shoved something in the microswitch to make sure that wasnt the problem. I think its either bad battery (undersized for the car) or more likely, bad motor... there is a full top w/ motor for $200 near me though, so this is more a time and labor issue than a cost issue. I dont hear the motor trying to engage at all so I assume this is the problem. It was left outside by a different bodyshop when this problem occured and they pulled the handle in the trunk and the battery died... I put the handle back but is there anything else I could be overlooking for a cheap fix?

- Third tail light - I have a new unit but it didnt work when plugged in. Hoping the unit is faulty and that its not the wiring loom at the trunk hinge or something else that could be a pain

- Speed sensor - odometer and speedometer isnt reading and I have a yellow brake/ABS/DSC lights on. Must be rear wheel speed sensor, yes?

- Replace fogs (one broke off while driving, found a nice set for the cost of 1 new one)

- Shift pins as time and $$$ permits (or trans swap to a 6 speed)

And upgrade parts left to buy or modify:

- Wheels and tires, I think I am going with some 135i wheels near me because they come with wheels and tires for $400 (then maybe upgrade to Alzors no thanks to Z@T and his amazing Performance 313s )
- Bilsteins with H&R or eibachs
- May paint my aluminum trim piano black... anyone have a wood trim with sport button they want to trade? I know these aluminum sets are pretty valuable, mine is not perfect but no major blemishes. I would like to do this but its becoming more of a hassle than I think it is worth

Already over budget on this project but I will finish it.
May need to sell it right after its done since I am spending my emergency funds on this car and that makes me a bit uncomfortable lol

Old parts are for sale, wheels, headlights, sidemarkers, taillights... buy some stuff to help defray my build costs

[Shipkiller]

Pull the microswitch and jumper it out first. It might just be a bad switch.

[Z4inAZ]

Originally Posted by Shipkiller

Pull the microswitch and jumper it out first. It might just be a bad switch.

Cheers. The top is the biggest nuisance right now, so next time I am with the car I will give this a shot. If jumping the microswitch fixes it, I can leave it jumped right? I just need to make sure to always keep the parcel shelf in the trunk down? And how many wires feed the microswitch, only two?

[Shipkiller]

Two wires.

Also, the silver arm might have fallen off the switch. This happens sometimes.

[Z4inAZ]

Originally Posted by Shipkiller

Two wires.

Also, the silver arm might have fallen off the switch. This happens sometimes.

I am not sure if there is an arm inside the mechanism you are referring to but, I see a silver arm intact on the outer portion of the mechanism. I tried to bend it a bit to make it easier to push but think I may have broke something... maybe I broke something inside the switch?

I hear it "click" when I push it, does that not mean anything (if not then I have renewed hope that I can fix it easily)?

Is there a specific procedure to resetting the emergency pull? Previous bodyshop pulled the emergency top release cable and all I did was put it back in place... is there any method to doing this correctly?

[Shipkiller]

If the motor is not corroded, the just putting it back into place will reset (actually releases the bypass ball) and allow the motor to port hydraulic fluid to the lifting cylinders.

[Z4inAZ]

Okay. Thanks for your help! I am still crossing my fingers I wont need to follow your top removal DIY Its easily the last thing on this car that could be big bucks...

[Vanne]

Looks good mate, coming together nicely. Hope you ave some luck with the pop-top.

[Z4inAZ]

Originally Posted by Vanne

Looks good mate, coming together nicely. Hope you ave some luck with the pop-top.

Thanks buddy! I cant wait to get her all buttoned up and driving Shes nowhere near as gorgeous as your M Coupe but she should make me happy for a little while.

[Vanne]

mate, you will love it, esp coming from the 3. Dont get me wrong man, I love the 3 also, but its a much more refined ride. and I also hear very good things about the SMG, so you /will/ have fun, guarenteed mate.

keep us posted with the progress.

[Z4inAZ]

Originally Posted by Vanne

mate, you will love it, esp coming from the 3. Dont get me wrong man, I love the 3 also, but its a much more refined ride. and I also hear very good things about the SMG, so you /will/ have fun, guarenteed mate.

keep us posted with the progress.

Aint no SMG here, shes a 5 speed

Im still clinging to my true manuals... may do a 6 speed swap if I decide to keep the car though. Mine is one of the very early production 5 speeds and I do a lot of highway cruising so the OD 6th would help.

[Z@T]

Finally you posting pictures of your Z.

You want to sell her when finished?

About your top not working, if the switch is fine, check the pump.

It is a common Z4 problem that the pumps housing is filling up with water.

[Z4inAZ]

Originally Posted by Z@T

Finally you posting pictures of your Z.

You want to sell her when finished?

About your top not working, if the switch is fine, check the pump.

It is a common Z4 problem that the pumps housing is filling up with water.

Yup, the project is nearing completion so thought I would make a build thread of sorts as we are on the home stretch here

I dont want to sell her, but I have a lot of money tied up in this and other projects, and the other projects are a much more stable place to keep my money so I will keep this car for a few months then she must go. Would like to be in a non-M Coupe someday soon

Really hoping the top problem is not a major issue, but its starting to look like it might be. The top for sale near me also doesnt include the motor so looks like I am up shit creek without a paddle right now. Going to go jump the microswitch right now and see what happens

Jumping the microswitch did not work... the motor isnt even engaging. It pops off the windshield frame but those are different motors, the main motor never tries to engage

Wanted to put the top down so I pulled the release cable in the trunk and the cable just pulled off. Guess its time to drop another $500 on this car... what makes me mad about this is the top worked the entire time I owned the car. I left it at a bodyshop to have them do some work on it and thats when the top broke. I think they just left it out in the rain. They pulled the release cable too.

This car is one headache after another... I no longer have any interest in spending money on this car but know the value will be destroyed without the top working... not happy

Actually I just realized how F'd I am. The top release cable broke, and its required to have the top lowered to remove it... without the cable, I cant release the top to lower it... any tips???

[spr_bimmer]

you can slowly push the top open once its unlatched from the windshield... its a slow process since you are just forcing the hydraulics but it will open...

[Z4inAZ]

Originally Posted by spr_bimmer

you can slowly push the top open once its unlatched from the windshield... its a slow process since you are just forcing the hydraulics but it will open...

Thanks... been talking with shipkiller and he said the same thing. This is gonna be a PITA I imagine. I hate dealing with convertible tops.


(this is the wrong part, lol)

[spr_bimmer]

that doesnt look like the right motor to me...

[Z4inAZ]

You are correct the correct part number was
54347193448
Hydro Unit

Went to the dealer to swap the wrong part for the correct part, also got the hydro rebuild kit for the washers, and new "sound insulation" - the parts will be here Friday

Started work today, pulled it out of the bodyshop and took it home.
For anyone doing this work without the top working, constant pressure against the top will open it as people here have mentioned. I also found "jiggling" it to help a little bit if it seems to get stuck anywhere. I did not have to undo the top trim and do the allen key trick (I think thats just if its not unlatching from the frame). My top seems to want to close from a half-open position (probably pressure in the hydraulic system) so I used a broomstick handle to keep it in line




Got the cable/harness stuff figured out. Thanks Shipkiller!!

Now I am trying to figure out how to route the wiring harness out of the car per the DIY... but I think I will call it a night for today and get to it tomorrow. I should only need to do 2-3 more things before the top is ready to be removed. Then I am going to try to figure out how to make the top motor watertight. I dont think overheating is too big a problem to worry about since it only runs in short bursts. I am thinking of sealing the sound insulation housing with silicone, on another Z4 forum I saw a member talking about this to prevent the problem in the future.

[spr_bimmer]

i sealed mine up with silicone.. i lost some hyro fluid in the swap and it takes a long time to engage... i will have to open it back up and add more fluid.

maybe i can get away with adding an inline nipple so i can fill it without opening the whole thing up again..

[Shipkiller]

Make sure you go to my web page and look at the PDF that shows you what the high and low marks are. Is BAD to overfill the system.

The new pump comes with enough fluid and they take into account that you will lose a little during installation.

Are you sure that the top is not binding, causing the pump to build more pressure to move the top?

[Z4inAZ]

I think I am going to seal the motor in it's housing with a bead of silicone all the way around following this red line. Any reason this wouldnt work?

Originally Posted by spr_bimmer

i sealed mine up with silicone.. i lost some hyro fluid in the swap and it takes a long time to engage... i will have to open it back up and add more fluid.

maybe i can get away with adding an inline nipple so i can fill it without opening the whole thing up again..

Ive been wondering about something like that myself... if it is in a sealed system where water can not ruin it, the only servicing it should really need would be to add fluid, so a way to add fluid remotely would be really great.

Originally Posted by Shipkiller

Make sure you go to my web page and look at the PDF that shows you what the high and low marks are. Is BAD to overfill the system.

The new pump comes with enough fluid and they take into account that you will lose a little during installation.

Are you sure that the top is not binding, causing the pump to build more pressure to move the top?

I noticed the new hydro unit had some fluid in it, didnt seem like enough, but will double check against your site before installing. For anyone reading who needs it, here is the link to his guide on hydro unit filling

The top does not seem to be binding, it can be a little tough to move (remember the emergency cable was not released, it snapped clear off) but does not move without the assistance of gravity. At first it would want to spring back when you moved it the first foot or so the hydraulics would move it, but once it is past halfway it is fine.

After I said I was done working on it last night, I went back and got everything else done except the wiring harness routing. Going to go to Home Depot to get a beefier set of Torx wrenches today (was adjusting some other stuff on the car and my bit stripped). Changed out the side view mirrors, look how nasty these were. I cant imagine any mirror being worse than my passengar mirror was...


There is a complete convertible top near me for $200 I may go buy... my top has a few blemishes and since it is almost out and that is the hard part, I figure it may not be a bad time to throw the other top on there.

[Shipkiller]

Look guys, I have said this many times and you all are not using common sense and good judgment.

This is a hydraulic system. It is a sealed system. If you need to add fluid then you have a problem and the root cause needs to be fixed BEFORE you address the symptoms (add more fluid).

The TIS does not tell you to add more fluid after you change the pump.

In regards with the question on sealing the housing, if you read the DIY throughly, you would see that is exactly what I did.

If the bypass is not set, the top should be very hard to move by hand if the hydraulic system is working properly and not leaking by internally.

[Vanne]

Auto dipping in those mirrors is shot. eBay has el-cheapo replacements, also makes the car slightly more modern looking without the boarders on the side mirrors.
Looks like your steaming ahead with the build. Keep us posted : )