Hello,

My car is due for a break fluid change soon. Before I start I read up on guides but still have a few questions:

1. Since the fluid is the same for the clutch and brake, should I change the clutch fluid as well at the same time? Guides don't tell you to do that, but it seems logical to me to do both at once.
2. If the answer to the previous question, will I be needing to bleed the clutch master cylinder ? (which, looking at ModMini video, seems a bit more complicated than just opening a valve) Hopefully I won't mess up and let air enter.
3. Some guides involve a bit more gear for pressure/vacuum, am I right that I don't need that if I have a helper to push the brake pedal?
4. This poster mentions a scanner to disable anti-lock mode, but it's not written anywhere else. What's up about that?
5. Any other "gotcha" that could be easily forgotten?

Many thanks.
A new hobbyist mechanic.

 

In theory yes if you want to be thorough but also if you want to sign up for substantial pain and suffering.

Will not comment on the brake side of the house; I have never done this but most likely need to.
On the clutch side:
Would watch MOD Mini's R53 clutch slave cylinder R/R again paying close attention to what he had to do to bleed the car.

Just replaced the slave and can confirm: these cars' clutch systems are a major PITA to bleed. Not trivial, not easy, not clean and definitely not fun.
>yes you will need a power bleeder (the buy sprayer pumped pressure kind like he had, the vacuum types will NOT work)
>yes you will need the jig / clamping mechanism he made or one like it to compress the slave piston for bleeding
>check around this board and elsewhere and you'll find the buddy system (a) takes forever and (b) isn't very effective. Get the power bleeder.

Get the front end as high as you can, tap the side of the slave body as you bleed, lay down plenty of cardboard and get ready to be drenched in a torrent of DOT4.

Also, even with the trick of propping the pedal to the floor overnight I was unable to bleed it completely and got maybe an 80% pedal by sunrise. At the time I was on the road and I had to drive the car for a few hundred miles with sometimes double pumping the clutch to get the car in gear before by some undeserved miracle, the issue resolved itself and normal clutch action resumed; would never have expected something like that to happen on any car, let alone a BMW product.

 

Thanks a lot for the answer.

The thing is, I'm not replacing the clutch slave cylinder, just changing the liquid. My thought process is: "there is already liquid in there, I don't need to drive air out". If I understand right, the "getting air out" is the annoying part.
In case of changing liquid only (with no air bubble inside), does that annoying part have to be done anyway?

Though I think I'll plan ahead anyway and start figuring out what I can use to have a jig like shown on the video. Knowing my luck, it's possible I'll mess up and let air inside anyway...

Also thanks for the power bleeder recommendation. I try hard to not buy too many tools (it adds up, and I'm already past half the car value in tools...) but that one seems pretty inexpensive (I saw some for under 30€, I will have to ensure it's "pressure" and not "vacuum" type).

 

True statement. Again in theory, ideally you have no air. But if you have just a little bit, anywhere - maybe some came down from the master, maybe some was already there, maybe you drop the slave and it tilts the other way, lots of things can happen.

As for the power bleeder, would check around and look to borrow one. Buddy, parts store, rental tool outfit etc. If you do buy one would recommend spend the extra few bucks for the one with all the attachments for other cars so down the road if you're working on another make (perish the thought of ever selling your MINI - you're here forever - but it happens) you'll be able to use it on whatever you're working on.

Will be watching this thread and seeing how it worked out for you (hopefully well with no issues) while enjoying not actually doing it, but knowing damn well I most likely will have to in the future. Good luck.

 

"Expect the best, prepare for the worst", so I'll do that thanks.

I actually found the exact one ModMini uses in his video and ... yeah it's not cheap (you'll guess from the ".fr" links that I'm French...).
Unfortunately I don't have buddies who are into car, and I highly doubt I'll be able to borrow one, since car culture is pretty much inexistant here and few people do their own car work, and as such there is no such demand/offer.

On the other hand, I found one for 51€, and someone in the comment even reviewed it as working perfectly for a r50! Seeing as how there seem to be a "E20" European standard, and I'm very likely to only work on European cars, I think I'll go with it (I'll advise in the future if I ever get a non-compatible car).

Anyway, thanks a lot. If someone else is reading, I'm still wondering about that "disable anti-lock mode with a scanner" thing for the brake part.

Edit : as for timeframe, if everything goes well, I should be doing it in 2 weeks. But don't hold me to that timeframe, I got more important matters first that could delay it if anything goes wrong. (if you're curious: power steering and coolant changes, fan replacement and a quick belt check while I'm in there)

 

In some (all?) cases a proper flush/bleed of the brake fluid requires the ABS pump be activated/cycled ("deactivated" is a new one to me) to cycle old fluid out of the ABS system and bring in fresh fluid.

It is best if you have access to a factory service manual that details the steps to follow to do a proper brake fluid flush/bleed.

NO MINI experience but I have bled the brakes (and clutch) of other cars. A power bleeder is nice. But do not think if some pressure is good more pressure is better. The advice I received and followed is less is better. If the pressure limit is say (just a number) 20psi I'd err on the side of caution and stay at 15psi. Brake fluid is not viscous and even a gravity bleed can have considerable benefit. (The worst of the brake fluid is heaviest and gravitates to the lowest points in the brake hydraulic system.) But of course a pressure bleed speeds up the process and if done right ensures all the old fluid is removed and replaced with fresh fluid.

I have found that with cars in which the clutch hydraulic system shares fluid with the brake hydraulic system a flush/bleed of the clutch hydraulic system *after* a proper brake fluid flush/bleed is really necessary. The brake fluid flush/bleed does not compromise the clutch hydraulic system -- at least in my experience -- but the fluid that is in the clutch hydraulic system is lousy fluid and I have experienced just what the lousy fluid can do to clutch operation when taking off from a stop and when shifting.

While I have had good experience with a pressure bleeder when doing the brakes when flushing/bleeding the clutch hydraulic system I have found the old fashion way of having a helper press and hold the clutch pedal down while I open then close the slave cylinder bleed screw results in a more consistent and good outcome.

Some cars have a clutch hydraulic system that while it shares fluid with the brake hydraulic system is supposedly "self bleeding". I never owned one of these cars so equipped long enough to see if that was true and if it somehow eliminated the need to flush/bleed the clutch hydraulic system.

Again I will mention it is best if you have access to a factory manual that details what if anything you need to do regarding the clutch hydraulic system.

Oh one piece of advise professional techs passed on to me was before one starts the flush bleed operation using a turkey baster remove some old fluid from the brake fluid reservoir then top up the level with new fluid. I was told this reduces the amount of fluid necessary to effect a proper flush/bleed.

Added: After I posted the above I reflected back on what I observed a tech do as he flushed/bleed the brakes (and clutch) hydraulic system of my cars. When it came to the ABS pump I don't remember him using the diagnostics computer to cycle this. What I recall is before he really started the service he connected the diagnostics computer to the car. Now I happened to recall reading about this computer (at one time I was seeking to buy one) and it offering a brake fluid service mode. It is possible this mode puts the ABS into some inactive state that allows fluid to flow through the ABS pump during a brake flush/bleed operation. I mention this because now that reference to deactivating the ABS makes sense.

 

I've never bothered with the clutch when bleeding the brakes, nor have I heard anyone mention doing it at the same time. Everyone says it's a pain, which could be why.

AFAIK, you should be able to use the two-man method for brakes just fine as a long as you aren't concerned about possibly tearing up seals in the master cylinder, but a Motive bleeder definitely makes things simple. I know that I've bled some pretty nasty brakes before and not had master cylinder issues from pedal bleeding, but YMMV I guess.

My understanding is that putting the ABS pump into bleed mode is really only necessary if you've run the master cylinder reservoir dry and introduced air into the pump, but I don't know for sure if that's true (I've never hooked my laptop up when bleeding brakes). I don't recall bleed mode being mentioned in the TIS, but I think the Bentley might mention it?

 

I bought a service manual (RTA, a French brand, which is similar to Haynes). The bleed procedure only recommend to use a power bleeder and never go above 2 bars (30psi), but doesn't mention that ABS pump. Even for an ABS pump replacement, it only tells to do the bleed procedure without talking about a scanner. Since my cheapo scanner doesn't do ABS and ABS-compatible scanners are expensive, I guess I'll forget about that.

Thanks, I'll keep those numbers in mind.

Thanks for the input! Since you nudged me to open the service manual, clutch fluid change is indeed recommended at the same interval as the brake fluid change.
For what it's worth, the manual warns about not exceeding 1 bar (15psi) for the clutch, half of what's recommended for the brakes. While it could be a typo (the manual has several typos like that, it's one of the reason I don't use as a prime source of truth), that could also be the reason.

Definitely not the case for the r50, there isn't anything to that effect.

Yeah as explained above my confidence toward the manual I own is not super high, and I value more feedback from people who actually did it. For example, the "working" clutch bleed procedure shown by ModMini is not explained in the manual.

Yup, that was planned, but thanks! I bought a cheap transfer pump specifically for that.

Indeed. I looked again, and the PelicanParts tutorial actually talks about that (I might have read too fast the first time around). They say it should only happen if you run the reservoir dry just like deepgrey said.

 

Just an FYI; there's a strainer in the brake fluid reservoir that you'll have to remove if you plan to suck fluid out. I've never bothered to figure out how to take it out when I flush the brakes, but supposedly it does come out somehow.

 

I tried to do it and it went .... very badly. The procedure seemed simple, but it did not account for 20 years old plastic.

The strainer was a bit of a hassle to remove but came with a bit of tugging with a needle-nose plier. It's retained by 4 small bulges in the strainer. But even if you remove it, you cannot really empty the whole reservoir because the bottom of it isn't easily accessible (or at least it seemed to me, maybe my pump hose was just too large).

Disaster struck when I pressurized the reservoir. The manual says not to exceed 2bars (30psi). I was pumping and aiming toward 20psi. At around 18psi (definitely under 20psi, I was recording and checked the tape), there was a pop, loss of pressure, and liquid on the floor.

After checking, the reservoir now leak fluid at the seam when under pressure.

So ... no brake fluid change for now, and my car needs a new reservoir.

Question time: can the car be driven with a reservoir that leaks fluid at the seam under pressure? I don't think it leaks fluid when not under pressure, and the level definitely isn't low.

 

In particular German green government-mandated recycled content plastic. The very worst there is. When you absolutely, positively want to ensure the car you manufacture and export to the world has a constant string of embarrassing material fatigue related issues throughout its useful life and beyond, accept no substitute...

I stopped at 15 psi on the clutch slave job, per Mod MINI's video but next time (if I don't sell the car first) I'll make it 10. Wonder how many of these have failed just on their own through normal use.

At least now we all know yet another weak point here in the BMW step child nation.

 

I drove a car with a plastic coolant tank that leaked coolant when hot and under pressure. But I drove it from cold just a couple of miles to the dealer. No leaks but the engine never got hot.

However, I would not drive a car with a bad brake fluid reservoir.

 

So I'm going to answer myself: I did a short trip just to test that there was no further damage. After a small fright about gears engaging without depressing the clutch pedal before starting, which fixed itself just after starting the car, it drives fine and there is no perceptible difference from before.

The reservoir level seem to stay stable just under the seam, which fortunately is above the minimum mark. Obviously, I'm not trying to drive any extended time with that, but short trips seem okay (since it's not my daily driver, it's going to stay parked until it's fixed).

I already ordered a new reservoir, along with a spanner and 2 new plugs for the master cyclinder. Total price including delivery: 100.58€ (half of it is the reservoir itself). Not too bad, and I guess it was going to break at some point anyway, better now in the garage than on the road.

 

Imo I wouldn't bleed it without a power bleeder , every time I've tried brake bleeding a mini they ALWAYS retain some air and the ONLY way I've been able to get it perfect is with a pressure bleeder. I also 50% of the time have to remove the rear line and bleeder screw and clean the crud out from in there too so that they bleed well and don't have any contamination in the lines. It builds up in the caliper behind the bleed screw so if it doesn't come out the bleeder , you'll need to spray brake fluid in and use a pick and compressed air or do what I did abd use a hose and blow into it into the caliper to blow out the crud..
but trust me , a powerbleeder will make things 100x easier.
I pump it upto 25psi too btw because unless your calipers have no contamination in the lines ,anything under 15psi wont even push it out..so if they don't bleed at 1st don't worry.

 

Reading all this, I feel so lucky when doing my engine replacement last year, I left my clutch hydraulic system intact and the clutch system was the same as ever when I hooked everything back up.

I like to bleed my brakes every couple of years but I have never bled or flushed my clutch line. In spite of my owning a pressure bleeder, it sounds like more of hassle than it's worth!

The last time I bled the brakes in my R53, I also blew the brake fluid reservoir and had to replace it. I didn't know the brake fluid reservoir is another common failure like the coolant expansion tank.

 

I don't think I've seen it as a common failure, but it's not hard to extrapolate that if r53s have a common issue in a pressurized plastic tank at ~15psi, another tank sharing the same design (plastic with a seam) is going to give in the exact same way when under similar pressure.
It's definitely not unheard of though, since searching for that issue uncovers a few people posting about it.

I'm still commited to finishing the brake and clutch fluid change once I receive the new tank. Again, might take some time, especially as last time I ordered parts on that site, it took 1.5 month to show up.

 

Update: new reservoir came in, it was a hour job to replace it, including filming, so probably a 30 minutes job without filming. Really easy stuff.
The reservoir included the cap and strainer. I now have an extra new strainer because I thought it was coming without (I was planning on re-using the old cap). Since they are easy to damage, it's not a bad thing.

The brake level sensor slides right out without any issue (at least for me).
The gaskets between the reservoir and the master cylinder didn't look like they had to be changed, and since they were hard to extract, I gave up and left them in. The reservoir slides right out and in those gasket without much issue.
I managed to access the single screw holding the reservoir by just removing the battery cover, without removing anything else. I changed it but you can probably cheap out and keep the crusty one.
The only tricky part was to remove the clutch hose. At first I thought it was a single part that was worn. Thanksfully, someone detailed it here: https://www.northamericanmotoring.co...placement.html In short, the hose is plastic, and there is a rubber gasket between the hose and the reservoir. You have to yank the hose out first, then remove the rubber gasket from the reservoir. To reinstall, put the rubber gasket inside the hose (you won't be able to re-attach the hose if the gasket is on the reservoir) then shove the gasket+hose on the reservoir.

The actual brake liquid change went as expected, though your mileage may vary depending on rust level. Rust-level is super low in my area, so no real trouble opening the valves with a bit of WD-40 specialist penetrant. I had a bit of trouble determining when it was "done" because the liquid color changes very gradually, but with a bit of time it was clear enough to call it a day.
I used between 14psi and 16psi all along. It's a bit slow, but better safe than sorry.

Overall, I used slightly less than 1L of brake fluid. I'll use another bottle fo the clutch later on. It took about 1 hour including filming, so you can probably get it done in 30 minutes (not including wheels removal and refitting).
I don't have the time to do the clutch right now, and can't risk having the car down for a while. If you're interested, that more recent thread may be of interest: https://www.northamericanmotoring.co...lic-flush.html

 

I remember reading this thread a few weeks ago but for some reason couldn't find it again (or I overlooked it) in my search.
I am a novice working on modern cars (Mini) and I am planning to preform the same flush (brakes & clutch) on my R53.
I'm sorry to read about your trials and tribulation throughout the process. This thread has shed new light on things to avoid.
You guys have really helped - not only @Fradow but myself as well.

 

Man, I'm a little late to this party, but the first brake fluid change can be a bit of a challenge, but once you've done it, it's really straight forward. I end up bleeding my brakes a couple of times a year if not more for track days. I love my motive power bleeder and FCP euro's lifetime replacement policy for all the Motul 600 fluid I've gone through. If your clutch is working fine, I wouldn't worry about bleeding it. I don't think it gets enough heat to really make problems, and the potential for headaches with bleeding is high.

 

Apart from the "reservoir rupturing" bit, it was pretty easy in my opinion. The only hesitation I had was to know when it was "clean" fluid. The color change is very gradual, and I'm not experienced enough to really know what's the correct gradient for "clean fluid".
Thanks for the input on the clutch. Indeed the potential for headaches is what's putting me off. On the other hand, doesn't that liquid age? There is a 2 year service interval on it, so I assumed you had to change it regardless of km driven / how hard you drive the car.

 

I wish they hadn't outlawed ATE super blue. You could alternate colors.

 

yup, I still have a sealed can of the blue in my garage, but I can't bring myself to use it.

 

List it on Bring a Trailer.

 

Since following this/@Fradow's discussion, while getting prepared to preform the same hydraulic/brake/clutch slave procedure on my own Mini; I decided to head out to a salvage yard and go through and R&R the hydraulic system using 2wo salvage yard Mini's as guinea pigs.
Prompted by @Fradow 's unfortunate experience having the reservoir pop while pressurizing the system - The first thing I wanted to investigate was the condition of the reservoirs on these 2wo 19y/o R53 junkers (mine being an '04 as well).
Here is what I discovered when I pulled the reservoirs on both salvage Mini's...


This is just one example of the failure point on these hydraulic reservoirs. This one hadn't ruptured *YET* - but the first reservoir that I pulled from another Mini had clearly blown (no pic), in the same exact area/corner.

FWIW.

 

Funny, that's not where my reservoir failed.

Sorry for the poor quality, I took that from a video, but it ruptured somewhere above my thumb on the picture, which is the left side when facing it, right at the seam:



The damage is not visible to the naked eye, but I could feel fluid coming out of there when adding pressure with the pressure bleeder, which was later confirmed because the fluid level dropped right at that level, not above or below.