2010 Summer Projects (CDV Delete Advice / Experience)

[Cloudbase]

The M Coupe hasn't seen much action since my spring projects (post here). I spent the later part of the spring enjoying my new hang glider at a competition in Florida - my longest flight was only 63 miles, but it did take 4 hours! Since I've been home my remaining M Coupe projects have been nagging in the back of my mind. Last week it rained for 3 days straight so I set to work.

Brakes and CDV Delete
The first order of business was to delete the Clutch Delay Valve (CDV). I ordered a stainless steel non-CDV clutch line along with stainless steel brake lines from Turner Motor Sports. I also got OEM rotors and pads and Euro Motorsport floating rotors and Hawk HP pads front and rear to swap out for the track. I glazed my stock rotors last year and my brakes had never been the same. While I was doing brakes I also got Turner's brass caliper bushing upgrade kit. New fluid was a must since I hadn't replaced it since my last track day, last fall. While the car was up I also replaced my transmission and diff fluid. I decided on Red Line MTL for the gearbox and 75W-90 for the diff.

SS CDV Delete Clutch Line



Installed



SS Brake Lines



Brass Caliper Bushings



Compared to Rubber OEM Bushings



Installed



New OEM Rotors



Installed



Stock Caliper Cleaned
(I was going to paint these red, but decided it against it because of heat dissipation)



SS Brake Lines Installed and of course new ATE Fluid





Diff and Transmission Fluids



CDV Advice
Removing the stock clutch line was definitely a pain in the ass, but it was completely doable. Don't be discouraged, its not that bad. I would even say that someone with no DIY experience could pull it off. I read up on the appropriate threads (here and here, here) and here's my additional advice advice. The problem is that there is no room on the upper end of the clutch line where it bolts into the hard line. You can only get one hand in there at best, so you need to set the wrenches up so you can break the upper line bolt loose with one hand. The set up I used is a 14mm wrench on the bottom (I had a buddy hold it from below, but you could also zip tie it loosely to the fuel lines so it doesn't fall when your not holding it) and a 11mm flare wrench on top. A flare wrench is a must! Both wrenches should form a "y" with the 14mm wrench closer to the block. Then I used my left hand from above to squeeze the wrenches together. It took a few attempts, but it broke with just my hand. Other threads recommend going from the bottom because there is more room, but I had better leverage from above. I used my left and because it allowed me to get better leverage than the right. Here's a drawing of the wrench set up:

Single-hand Stock Clutch Line Removal Wrench Positioning
I CAN'T REMEMBER WHICH WAY LOOSENED THE COMPRESSION NIPPLE SO MY DIAGRAM MIGHT BE BACKWARDS - I'll check in the morning.



Bleeding the Clutch Slave Cylinder
I used this thread as a starting point (here). In the CDV threads linked previously ClintJ's method is mentioned. That is to compress the plunger with the bleed nipple open to purge air out then close the nipple before releasing the plunger. The best way is to squeeze against the side of the transmission. I couldn't manage to hold the plunger all the way in while closing the bleed nipple. It might have been easier with two people, but I was solo at that point. Paranoid that there was still air trapped in my Clutch Slave Cylinder I decided to bleed it the factory way. The problem was I didn't have special tool 21 5 030 in the thread above. I was able to make one similar in about 20 minutes out of parts I got at Lowe's for $25. I drilled 3 holes in a piece of 1/8" thick steel, used two 6" long 1/4" bolts for the sides, and a piece of 5/16" all thread with a nob on the end to compress the plunger. Here it is:

Homemade Version of BMW Special Tool 21 5 030



Special Tool in Use
(when opening the bleed nipple make sure it is positioned so the bleed nipple is highest)



The homemade tool worked like a charm and I had the whole system bled in 20 minutes.

Impressions
I only drove about 10 miles around a loop near my house to break in my new pads and rotors. The clutch catch point has moved closer to my foot. I think this is due to a fresh bleed and not the CDV delete, but it is taking some getting used to. At least now it's consistent. My shifting is noticeably smoother with the Red Line MTL. The brakes don't feel quite right. Perhaps they need more breaking in, but I feel like there might be a tiny bubble somewhere in the system. I'm probably being paranoid, which is normal! I'll have to drive it more to tell.

The last thing I did was replace my Chromium rings with LED Orions on my PZ II's. The Orions are so much brighter than the Chromiums. I'll try to take some pics soon.

[JWin]

As far as the brakes, if they don't quite feel right, absolutely bleed again. It will likely improve a lot. It's kind of boring but it's easy and totally worth it.

[cngizbleevng]

4 hour hang glider flight? Is it a motorized version? I've been thinking about getting into ultralights.

[Cloudbase]

Drove it this morning and the brakes don't feel spongy like there is air, but I was hoping for a more solid feel. I'm going to put some more miles on the pads and rotors and see if they improve.

The 4 hour flight was unpowered, although in Florida we tow up behind an ultralight. I've flown the ultralight a bunch, so much fun. Def would recommend pursuing that.

[Robstah]

Is this a track car? I wouldn't recommend brass bushings on a street/even light track use car. They require way too much upkeep.

[afb]

nice...here's my el cheapo clutch slave tool

[Robstah]

You know, you guys could just pump it with your hand until it get unbearable, and then pump it a couple of times into the side of the transmission. That's what I do and it seems to do the job just fine.

[sennasixty8]

did you bed in the pads and rotors with several 5-40-5mph runs, allowing for cooling and no fully stopped intervals?

[fletch138]

Great Thread. I just got my UUC CDV line in the mail. Wanna help me install it? Btw, let me know if you ever need an extra hand, I'm down in Denver with an s54 roady and will jump at any opportunity to help work on our cars and learn.

FWIW, I just did my diff fluid too. I read around a LOT and I thought I read Randy and the veterans on the board saying the S54 M's get 80w140 for the diff.

[Cloudbase]

Is this a track car? I wouldn't recommend brass bushings on a street/even light track use car. They require way too much upkeep.

It's a 2-3 CCA HPDE's a year kind of track car. Just the occasional opportunity to stretch its legs. What maintenance is required vs the rubber ones?

did you bed in the pads and rotors with several 5-40-5mph runs, allowing for cooling and no fully stopped intervals?

I didn't bed them that way. I did a loop near my house that has several 35-65 to rolling stops. My local indy guy told me just to take a couple laps around the neighborhood. I put another 40 miles on it today in mixed traffic and they are getting much more solid. They still don't feel as good as the brakes did when I purchased the car.

Great Thread. I just got my UUC CDV line in the mail. Wanna help me install it? Btw, let me know if you ever need an extra hand, I'm down in Denver with an s54 roady and will jump at any opportunity to help work on our cars and learn.

FWIW, I just did my diff fluid too. I read around a LOT and I thought I read Randy and the veterans on the board saying the S54 M's get 80w140 for the diff.

I'll help you do it. I'm in Superior. I've got a mixed schedule the next couple weeks. Weekdays are better for me as I usually work weekends. We should flush your fluid while we are doing it, it'll only take about 20 minutes.

We should also go for a drive in the mountains. I've got a few Z3M owners I can call to join us!