I am following your "soft brake pedal" journey very closely as I am having the same experience. Last time I bleed the brakes, I read this on Pelican. If you find that your ABS equipped car feels spongy on the brake pedal, take the car to a deserted parking lot and engage the ABS system by stopping short a few times. Then go back and re-bleed the system: it may take care of the spongy pedal, although this not a factory recommended procedure and it may not eliminate all the air from the system.
I just did a full brake fluid flush yesterday and again I have the soft pedal very similar to your experience. I went out yesterday afternoon and got into the ABS pretty hard and I'm going to re-bleed today using the BMW / DSC technique you mentioned. (I don't have the Schwaben, but if it works, it's going on the buy list)
Keep up the posts and thanks.

 

I believe the Schwaben tool helped. I watched the clear tube very closely when exercising the ABS pump ("ventilation" option in the scanner), and I could see small (really small) bubbles coming through the fluid. As you, I went out and exercised the heck out of the ABS...did it twice. Once to bed in pads and again just focused on brakes. Unfortunately, I did not see any improvement after that. Also, had my shop make a go at bleeding when I got it aligned - no significant change.

I am not sure what to do at this point. I ordered a used R53 brake MC from ebay so I could take it apart, but it never came. I gotta get back on that. But, I have the OEM MC that I can mess with, but I hate to do that since I think it is still good. I know some people have put M3 master cylinders in R53s, but have not found decent documentation. Maybe the mini MC could be bored out so it creates more pressure with less travel? That would be expensive, but worth it if it worked.

I might buy a couple old/used M3 master cylinders to see how they might fit.

I believe this is going to turn into an R&D project!

I am super busy for the rest of the month, so may not get much done. If you have any ideas or great findings, please post!

 

I'm also curious and following your journey closely. I did my first track day with the r56 brakes and honestly didn't mind the pedal travel and was really happy with the heat tolerance of the brakes. My front calipers and discs measured around 300 degrees F after a cool down lap and I had no real problems with fade.

I thought I'd share this, you've probably seen it, but I think it's the best documentation of the M3 master cylinder swap
http://r53trackcar.phatphoto.com/201...cylinder-swap/

 

I am making a run at Ate to see if I can get connected up with someone in their technical department. I want to get drawings of the MC and/or see if they can help identify another MC that would fit.

I bent a wheel at the track, so only got one day in (Friday). Luckily I live close to VIR, so went home and brought the GT4 back for Sat-Sun. Driving those cars back-to-back on the track has motivated me even more to fix this R53 brake issue.

I was again planning on doing the brake duct test, covering one duct up and measuring the diff in rotor temps, but since the Mini's weekend was cut short, I was not able to do it. But, I did check rotor temps after a 30 minute session and they were very cool - less than 400 F. But, that is after a 0.8 mile cooldown on the back straight.

I don't think I mentioned that I fitted BC coilovers before the track day. Had no idea how to set them up, but put them on about 22/30 where 30 is hardest .Very different and took me a while to get used to them. I discovered yesterday that the front axles are rubbing on the sway bar link. :( Does not look like a terribly bad rub, but will have to look into it.

 

Pretty slick looking setup. Cutting the strut towers makes me kind of nervous though.

 

Agree, but I figured between the camber plate and strut tower brace there's a lot of meat there and the sidewalls (semi-vertical surfaces) of the strut tower carry most of the load anyway

 

Apparently aftermarket endlinks are often too long and will rub. OEM seem to fix this.
https://www.northamericanmotoring.co...ting-axle.html

 

Still working on the R53 brakes. My conclusion after replacing the master cylinder and using various bleed methods is that I still have air in the system, somewhere. I plan to use a push and pull method, adding suction to the calipers. Have not done that yet. Also, seeing how the fluid makes its way around the seals in the MC was somewhat enlightening. You are only going to get so much flow because the fluid has to squeeze by one-way seals inside the MC to get out.

In the meantime, I ordered a used MC and cut it apart to check out how it works. Made a video here if you are interested:

 

Well, it's been a while and I have finally declared victory on the brakes! I ended up ordering a BMW E-46 M3 master cylinder to see if it would fit. The diameter of the part that fits into the brake booster is the same. After taking it apart and seeing the MC piston is slightly larger than the OEM mini MC, I decided to install it. Took a long time because it was the first time I had done a brake line. And, to boot, I used a very-hard-to-bend stainless steel line. The E-46 MC was slightly longer, so I had to make some cuts in metal to make it fit. Here is one of the initial test fits. I was able to re-use the rear-most brake line in this view.


I had to adapt the brake fluid reservoir seals a bit from the mini reservoir to fit. The basic diameter of the bottom of the reservoirs is not the same, but you can make it work.


Here's a shot showing the new stainless brake line and parts I had to cut to get it to fit.


Here is another view.


I had to buy a $200 to create the bubble flares on the hard-to-bend SS brake line. At some point when trying to get the new line in, I ended up having to remove the ABS module. I really did not want to do that due the massive bleeding that would be required afterwards, but had no choice. Turns out the bleeding wasn't that bad.

I installed a small spacer or extension on the rod in the brake booster. Had to do this because the relative distance from the MC mounting flange to where the MC engages the brake booster rod/shaft was slightly different. I re-used the brake pressure sensor from the Mini OEM MC and plugged the additional one on the E-46 MC.

All this took many weekends of off and on work. Lots of installing, fitting, adjusting, and trying again. Lot of cursing at times

In the end I decided I did not want to do all this work and then find out my problem was in the front calipers, so I got a Willwood big brake kit. The Willwood caliper and rotor weigh significantly less. I can't remember the number (I wrote it down somewhere), but it saves at least 5 lb per wheel.


The first time I took the car out, I was initially highly disappointed. However, what I figured out was the pads that came with the kit are the cheapest ones available and they need to get hot before they work well. So, I ordered the highest grade Willwood pads and put those on. Just bedded them in this past weekend and wow! Big difference.

I ended up re-installing the original brake pedal and removed the one I had modified to move the brake pedal closer to the gas pedal. At some point I even cut off the Rennline pedal extensions to try and get heel toe sorted out. Now that it is all good again, and I just re-ordered the Rennline pedal extension ($50) so I can use the foot-roll method to heel-toe. I will use the extension on the top of the gas pedal.

The new pads work very well and the pedal is hard and does not go down excessively - it feels normal. Note however, this is after a bunch of bleeding. I bought a gallon of cheap fluid to get all the air out and then flushed it with RBF 600 as a final step. I believe somewhere above I talked about using the Schwaben scanner to run the ABS module during bleeding to help get all the air out. That was an essential part of this process.

I am scheduled to take the mini down to RRR in early February!

I also replaced the OEM hood with a fiberglass hood - saving 23 lb. It was an enormous pain to get it to fit - took way too long. I initially ordered a carbon fiber hood, but they do not make them any longer. It took them four months to tell me that :( I suspect the CF hood would have fit better and required less 'customization.'

 

Nice wilwoods! You are going to have some stopping power now, also they fill out the wheel well nicely.

 

"I don't think I mentioned that I fitted BC coilovers before the track day. Had no idea how to set them up, but put them on about 22/30 where 30 is hardest .Very different and took me a while to get used to them. I discovered yesterday that the front axles are rubbing on the sway bar link."

Hi, I have a 2006 R53 JCW (Australian) which had the same issue with the end link rubbing after installing BC Coilovers (DS/DH), I ended up taking it to a suspension "specialist" who decided that raising the front & rear coilovers approximately 2.5cm would fix the issue (well it did I guess) but made the car look like an suv. Admittedly It was also handy as I had been doing a lot of very long country road trips along gravel roads while camping throughout our state last year in my JCW. I was going to tackle correcting the front ride height sometime this week and came across your thread.

I have a Superpro adjustable rear sway bar and Superpro adjustable rear end links so thought I would check if they had ones for the front end of the R53. From their website (Superpro) it does not appear that they do, but I did come across the following from the Orrange website in the UK:

https://orranje.co.uk/product/superp...sway-bar-links

"Front - TRC10200 - Adjustability Range of 245mm to 305mm
Please note these may need to be installed 'backwards' at one end, compared to the OEM droplinks, due to the extra thickness - please contact us for more info.
Rear - TRC10160 - Adjustability Range of 210mm to 260mm (these are what I have installed at the rear of my JCW)

Please note that as these are thicker than standard, clearance between components will be different, and may need to be fitted backwards as noted above. Clearance is also dependent on the coilovers you have and the level of drop you have them set at. You must also set the droplinks to the required length (ie longer or shorter, depending on if you are fitting to the front or rear), and fit them with both wheels in the air, and check clearance with both wheels on the ground."

I used the end links that came supplied with the BC coilovers but obviously they rubbed only on the drivers side (right hand side under acceleration while cornering during a right hand turn). Reading some of the responses above it would appear there may be some merit in checking if the sway bar is not aligned correctly based on my circumstances. I believe the OEM end links were longer than the BC ones though I will need to check once I get around to comparing them again.

I thought I would throw this info out there for you as it may help in curing the issues you are having and I only came across the details from the Orrange website because I was looking for a specific brand of endlink.

It is really difficult for me to work on my car due to spinal surgery so I do things in small steps & it is likely the car will be on jack stands for a week just to do this one small job. Will see if I can either simply swap to the OEM end links or see if their has been some movement in the swaybar when I initially installed the coilovers and endlinks. I will post back once I have had some success (or not).

 

Finished adjusting the BC coilovers on my JCW. No issues with rubbing on the axle. My son has a 2004 MCS with the sports+ suspension which I believe is 10mm below stock. The suspension place I took my car to had raised the suspension to 10mm over the stock sports+ height. I lowered the front by 20mm and everything seems fine. Had to tighten the nut below the adjusting **** on the coilovers as that had started to work its way loose. I am guessing the issue with the rubbing on the axle is due to the ride height being set too low?

 

The car is definitely sitting lower. I did not do it purposefully. When I had it aligned, I had the shop check it, so maybe they made adjustments. I may be wrong but I think/hope it only rubs when turning sharp - at least I hear a noise and seems like it could be the axle rubbing. I looked at it on the lift, but the wheel hangs so low, you can't really tell what is happening. I'll have to take a closer look this weekend. Going to the track the weekend after that.

 

Went to Roebling Road (near Savannah, GA) last weekend. The Mini was awesome!

Link to video: Note the speed/RPMs/etc. lag by quite a bit due to the slow update rate on the dongle. I have a better dongle (Kiwi) but could not find it.

Anyhow, there is still room to improve the set-up, but at least it didn't hinder any of the fun factor. I had the most aggressive Willwood pads because the pads that came with the brake kit were the lowest grade (cheapest). I believe they have 3 or 4 grades, and what I had at the track was the most aggressive. I am definitely going to back off, and maybe even go back to the original (cheap) pads. The brakes are so grippy that without much pedal pressure it is engaging ABS, especially when I was trail braking. I'm typically used to rear-wheel drive, so not sure if trail braking in a FWD car is recommended or not, but it works like a charm and helps turn in. But, I suspect the inside tire is locking up a bit and causing the ABS to engage. It was noticeable but controllable. Of course I turn DSC off.

My heel-toe was minimally acceptable. Lots of room for improvement there too. I re-bought and re-installed the Rennline gas pedal extension (that I cut off about a year ago), but only installed the top aluminum part. I'm going to get a tune from Adrian to improve gas pedal response, and I believe that will massively help the heel-toe situation.

I was very impressed with the overall grip and stability of the car. RRR is mostly long high-speed sweeping turns, but I kept pushing and pushing and the car just stayed planted as I decreased lap times. I am using Kuhmo Ecsta tires. They make a lot of screeching noise around the turns which is annoying, but I'll trade noise for grip any day.

The headliner seems to be giving up, so I may be tackling removal of the foam. I read about it a couple years ago and seems like a very crappy job to undertake, especially with one bum shoulder.

I got some photos of the axle-link rubbing and did a bit of investigation on it. I do not believe it happens until the wheel is turned just about a full 360 deg, which does happen a lot in parking lots, but not on the track - at least not RRR. Also, in my case, I believe the axle is touching the sway bar link joint and not the vertical bar part of the link. I'm heading to VIR at the end of February and turn 4 (I believe) is very sharp - might have an issue there. Will have to think about this some more...

I was with a Porsche club and driving in black (advanced solo), so my arm is still sore from giving point-bys (haha), but the Mini held its own in the turns. With some improvement in heel-toe, I will be able to do more shifting with confidence, and that will help me burn a couple more seconds off my lap times. As it was, I should have been shifting down to 3rd in at least 3 places (just before turn 2, just before turn 3, in turn 5), but a lot of times would just stay in 4th. Never made it to 6th on the straight, but I can see getting there with a few more tweaks.

Also, forgot to mention, in checking my brake temps, they were very low. Rotors in the 200s and caliper in 100s after getting back to the paddock (I've seen rotors in the 600s at other tracks). RRR is not a brake-heavy track, and with more track time, I will get more aggressive on the brakes. But the bottom line is that the brake ducts seem to working well.

 

Well, not a great weekend at VIR. I literally was out for my first session, had just passed the start/finish line, hit the gas and lurch...went to limp mode. Not a great feeling limping at 20-25 mph around the full course haha, pointing the field by me 2x. Luckily I was able to pull off to the left at the start of the back straight and go through a gate and drive back to the paddock.

I believe it's the MAP sensor.

P1868 and P0107


manifold absolute pressure sensor

Using the scanner, I looked at the live MAP data and it was zero. I will try to test the sensor before buying a new one. Will try to post those results.

 

I wish I could get my OBD to link up. Have 2 Bluetooth scanners and neither can connect to the ECU. I saw a you tube video of someone who had the same issue & he showed how he traced it to a wire that had rubbed through in the engine bay. When I feel like tormenting myself I'll see if I can track my issue down.

How did you find the BC coilovers? I finally drilled to allow the rear adjuster cables to be fitted and have been playing around with the settings. May even look at setting the rear sway bar to the stiffest setting too.

 

I can't recall where I got the BC coilovers - get them last year. Maybe from ECS. I also drilled holes for the rear adjusters. I have them set in the middle. Have not had a chance to experiment at all (yet).

I put on a set of cabriolet engine bay supports last Friday before going to the track. Would have been nice to try them out.


I am wondering if I also have a wire harness issue. The sensor itself seems to be functioning. I am not sure if the voltages are correct, but the sensor is certainly responding to pressure changes. Made a video:

 

I put the intake back together this morning after trying to find the issue, but did not find anything. I wanted to try hooking up my Cobb access port to see if it might tell me something I didn't know. I started it and within about 5 seconds the CEL cleared (turns out the Access Port won't work on this car). I took it out for a drive and it was great. Until about 5 minutes in, and it went into limp mode again. But, after I limped back to the house, I did another round of spraying with starter fluid. Low and behold there is a vacuum leak around the brake booster. I was very glad to find it to finally have a solid diagnosis!
Did not go beyond that, but I assume the actual problem will be 'easy' to find - either the vacuum line or booster itself.
Made a short video to show the starter fluid spray in that area.

 

^^^ Somewhat coincidentally, watched your Cravenspeed SSK install video again a few days ago after @Oldboy Speedwell linked to that in my related thread topic with plans to revert from SSK to standard actuation. I was curious what else MINI-related on your channel and watched with enjoyment the only such vid I've seen wherein a BaT bidder records real-time action and comments (including your SO on the phone) to winning conclusion. Great fun, despite not many views! On same channel, pleased to see you still own this R53 JCW 4 yrs later and track it occasionally. Well done!

 

You took out your intake flapper, so there's a hole right on the other side of the brake booster that leads directly into your intake filter. It took several seconds for the idle to increase, so i would assume it was floating around a bit prior to being sucked into the intake.

 

Wow! I bet you are 100% correct. I can't believe I didn't think of that. With no flapper valve there, surely the fluid went into the intake...Thanks for the post!

 

Enjoyed reviewing this thread. Nice car. I'm not sure I would have turned a cherry JCW into a track car, but it's your car and it's whatever makes you happy that matters. Like me, you seem to really enjoy working on your MINI. I think I enjoy working on the car as much as I enjoy driving it! Okay, well, working on it is a close second. 😄

 

It's still street legal, and thanks for the note!

 

I gave up on the CEL and manifold air pressure code and took the car into a local Mini/BMW shop. I needed Air Conditioning fluid, so figured they could do that too. They replaced the MAP sensor, which is the same thing I did, and, alas, the problem is fixed. I don't understand it - I bought a brand new sensor (although not OEM) months ago, and the issue remained.
I really didn't believe the new MAP sensor was the final fix, but after I picked it up I drove it to work and home - fine. Yesterday I took it out for a bit of simulated track driving. Got the engine up to temperature and took it to this place I found with a small oval - fine. Drove it on the highway, parked for an hour, went back to oval and back home - fine. So, it seems to be ready to go!

BTW: not sure if I have mentioned this in this thread or not, but if you are going to the track you must turn the DSC off. I am not exactly sure what it does, but whatever it is, it feels like it is trying to make sure you don't go too fast

 

Had a fantastic time at Roebling Road Raceway (RRR) in Savannah, GA this past weekend (Porsche Club of America (PCA) event). A couple of interesting laps on video where I am pointing by cars on the straight:


Completely wore out the tires (Kuhmo Ecsta). Had a pretty good chunk taken out of one, I believe due to me running over a curb. I moved it from front to rear (left side), and it survived the whole second day without the chunk 'spreading.' I was a bit surprised.

I ran in black group and was by far the lowest HP car there, except for the spec Ford racecars, but obviously those guys are superfast even with low HP. The mini held its own and got rave reviews. I was able to hang in the curves with half the field and enjoyed numerous point-bys by a 911, Cayman S, and a Cayman GT4 (of course all in the turns). I was hanging with a GT3 for three laps until they pitted. The GT3 obviously pulled me big time on the straight, but by the time we came around again, I was close

If you know RRR the last big turn onto the straight is Turn 9. I am close, but not there yet, to going flat out through that turn and onto the straight. With new tires, I think I can do it which might give me nearly a second. My best was just into the 1:24s (like 1:24.8). The Garmin says my optimal is 1:23-something.