Roof drainage channels - Advice please

[Zmachine]

Hi.

I know it's covered on here a fair bit but I still can't find a easy to follow full step by step guide.

I need to clear my roof drainage channels once the hard top comes off for the warmer weather. I've heard this can cause a common fault with the roof motor failing if not done on the earlier Z4s.

There is a guide on bimmer forum but the images won't load so its not very clear.

What tools are required and do you need to jack the rear end up and remove the wheels to access the covers?

Any advice much appreciated please!

[RJS-Z4]

I found an easier way than any of the suggested or written routes this weekend.... seriously.

Half open the roof, get your hose, and fill the "back bit" with water.

Now, you should be able to see where the water is draining on either side, whether slowly or quickly... Now, get your hose, point it down there, pinch it off, then let it go. The pressure of the hose soon clears it out, and then the water will run down it like a waterfall. Works perfectly on both sides.

[Jembo]

I found an easier way than any of the suggested or written routes this weekend.... seriously.

Half open the roof, get your hose, and fill the "back bit" with water.

Now, you should be able to see where the water is draining on either side, whether slowly or quickly... Now, get your hose, point it down there, pinch it off, then let it go. The pressure of the hose soon clears it out, and then the water will run down it like a waterfall. Works perfectly on both sides.

Did mine on Sunday... using the old take it apart method underneath & rammed a bit of rubber tube upwards. Had been bugging me for years, though fortunately not much grime had collected

[RJS-Z4]

I haven't done that yet Jembo, we were detailing the car last week and doing a deep roof clean when my mate just shoved the hose down there, suddenly the flow increased 5 fold, so we did the same on the other side. Seems to clean them out perfectly.

[Zmachine]

Ok thanks for the guidance. Where are the underside drainage holes if using the standard method ?

And do you not need to open these to release and debris ?

Sorry for all the questions it's just bugging me thinking they may not be clear!

Thanks

[simvaughan1]

There is a rubber bung underneath. If you jack up the rear wheel (and put an axle stand under to be safe), then you can feel around just infront of the wheel under the sill for a rubber bung.

Here's what I put on my thread about a month back http://www.z4-forum.com/forum/viewtopic.php?f=2&t=46362:

I then sorted the roof drains out. Used a welding rod and some tubing to poke, blow, suck out the grit. I then flushed them with water. Both were blocked up. Here is some of the grit that came out of one side. Note, I didn't disasemble anything, I just jacked the car up and reached into the space and pulled the plug out. At first I pulled off the rubber grommet and spent about 30 minutes getting it back on before realising the whole plug comes out!

Note that once you get a feel for it, you can poke something up from the top and the bottom. Mine were well and truly blocked (albeit with not much grit), but it all came out and the water flowed nicely.

[Zmachine]

Nice colour choice btw jembo

[andysat]

Did mine at the weekend and left the bungs out.

[Zmachine]

Thanks simvaughan1.

Great job on your car aswell, looks fantastic.

[Shamu1982]

Does the roof channel problem affect all cars to 08?