So it's that time.... again.
I have just ordered a Schwaben power bleeder to flush my brake/clutch fluid.
I've never done this on a modern car before. I have taken ques from previous posts and will take great heed so not to have any adverse problems arise.
While looking to purchase DOT4 hydraulic/brake fluid at my local car part store - I noticed 2wo versions = Regular DOT4 and Synthetic DOT4.
What is the difference and what do you guys recommend?

BTW: I will be preforming the flush procedure by myself. I am not sure if I can or will bleed the clutch slave by myself.

Thanks.

 

You can. It's only a pain if you don't have a tool to compress the slave. Well, you'll never get it bled if you don't compress the slave, regardless of how many people you have helping you. I hand formed one out of a thin sheet of steel and drilled two holes for the mount bolts to attach, and a third hole in the middle to hold the slave 'nub'. A steering wheel puller will also work in a pinch if you have super long M6 bolts handy. Just don't be like my silly friends and try and use this to actually build pressure in the lines. This is for fully compressing the slave, and pumping the pedal a few times with the screw OPEN. Keep a column of fluid in a hose above it.

Reinstall the slave. Do the same thing. Open the bleeder screw with a loop of hose on the bleeder, let gravity fill the hose 3-4" and get in and work the pedal yourself, working the pedal slowly. There isn't much wiggle room in this procedure. Either you compress the slave, bleed, install, bleed.....or you have a loose pedal.

 

If you're "just" flushing the brakes and clutch slave you don't need to "bleed" anything. If the clutch/slave is working fine then you don't have any air in the system and a normal flush procedure done right shouldn't introduce any air into the system. Bleeding the system is done the same way so I'm just being picky on the wording used.

Process I've used for years:
The car is completely off, no key in the ignition, etc.
Use something to suck the old fluid out of the reservoir - turkey baster, hose and suck it out, etc. I use an old infant nasal aspirator suction bulb from when my kids were young.
1. fill the reservoir with fresh fluid
2. Put clear tubing over the nipple on the caliper or slave cylinder, and the other end into a jar to catch the expelled fluid. You'll have to figure out the right size tubing to get a tight fit on the nipple, maybe .25" ID. You can buy clear vinyl tubing at a hardware store. You'll only need about 2', some stores sell it by the foot (in the US)
3. have an assistant lightly push in the clutch or brake pedal and HOLD
4. use a wrench to open the bleed nipple and let the fluid flow out through the tubing and into the jar. The peddle will slowly go to the floor.
5. close the nipple - Always close the bleed nipple before letting up on the peddle!
6. Let up on peddle slowly
7. go back to step 3
Keep repeating this process until you see new (it should be clearer) fluid coming out of the bleed nipple.
**Every 4-6 brake peddle pushes refill the fluid reservoir, don't let it go too low and introduce air into the system! After a few cycles you'll get a feel for how much is pushed through the system with each peddle push and can gauge the frequency of refill.

The process is pretty simple. It just takes patience and a couple of tools.

If flushing the brakes start at the wheel furthest from the reservoir and work your way closer.

 

I'm not sure what synthetic means in the context of DOT 4 brake fluid. It sounds more like marketing to me than anything meaningful, but maybe there's something I don't know.

I run ATE TYP 200, which is probably complete overkill for my application.

Pressure bleeders make brake fluid changes soo much easier.

 

Thanks guys for the informative and timely response.
Well, the Bentley manual answered my question = standard DOT4 brake fluid.
@deepgrey I have to concur with your assumption regarding the "synthetic" branding. Although I admit I'm a bit clueless when it comes to knowing the difference.
I will probably forego the clutch slave bleed.
I will be using a pressure/power bleeder and the same procedure that I've used in the past as also outlined by @RudeJoe.

BTW: How many quarts does it normally require for a "typical" bleed & re- fill?

On a side note:
The issue that has caused me to move forward with a flush is that I've had; when driven hard (high rpms) or 25+mi hwy or stop & go intown, it soon becomes difficult to slide/shift into gear. This only occurs when the car is warm/hot after driving.
I suspect there is moisture in the hydraulic fluid. It was brought to my attention that when the moisture gets hot and expands in the hydraulic system (as mentioned by @RockC in another thread).

I had the hydraulic/brake fluid flushed about 5years/18kmi ago by a BMW certified Mini garage. I began to notice the issue developed 2.5 years ago (-15k +/-) when my commute changed and required me to travel on the express way.
Apparently I am a few years overdue for a fluid change. I preform a transmission fluid change every 6k-8kmi (Redline 80W MTL) - It has always shown to be translucent and topped off/Max so I have ruled that out to be the cause.

I have the Foxwell 510N Elite. I believe it has the ABS activation capability as one of it's features. I'm pretty sure I had seen it during one of my routine scans testing the fan, injectors & MAP sensors...

Any additional input is welcome and greatly appreciated.

 

My recollection on brake fluid is; DOT4 is hygroscopic while synthetic DOT5 is not (however DOT5 being more caustic by comparison). My buddy and I flushed both our Can-Am UTV brakes recently (plus new pads) and we double-teamed flushed using fresh Motul DOT4 with my MityVac vacuum pump. Worked quite well but a simpler hydraulic system than R53 despite still having dual master cylinder reservoirs.

 

One quart should be sufficient to bleed the brakes but I always have an extra on hand just in case.

 

If you are having issues with shifting, I wouldn't forgo bleeding the clutch slave. if there's moisture in that line causing a problem, then bleed that to eliminate that cause of the issue. I just flushed my daughter's Countryman brakes on Sunday with my Motive pressure bleeder, I ran through about a pint and a half of fluid. As you work from the back, you'll need to drain more fluid to get it changed out. there's no need to run the ABS pump according to my conversations with a bunch of well versed BMW techs that I know UNLESS there's air in the ABS valving. From what I was told, that only happens when you drain the brake system, so you should be ok from that perspective.
HTH,

 

Question: If I were to keep the clutch pedal depressed with a length of wood while pressure bleeding the hydraulic system - After bleeding/flushing the brakes is complete, - Would releasing the clutch pedal thereafter draw in fresh fluid into the clutch slave?
Thanks.

 

I don't think you want the clutch pedal depressed. The official instructions say to attach the pressure bleeding tool, pull the slave cylinder from the bellhousing, attach the special tool (or hack tool as shown above), then open the bleeder valve. When the fluid runs clear, close the bleed valve, reassemble, and check pedal free travel.

 

Yeah, that won't do anything. If you just bleed the brakes with the clutch pedal depressed and then let the clutch pedal up, you'll force old fluid from the clutch line into the master reservoir basically contaminating the new fluid. There's no shortcut to bleeding the clutch properly other than not depressing the piston and just bleeding from the bleeder. If the clutch is the issue, bleed the clutch properly and be done with it.
Just my .02

 

Ah. Thanks guys.
Even though I've heard it time and time again = R&R and bleed the clutch slave (procedure)...
Wishful thinking on my part.

I guess there's a first time for everything.
Wish me luck!

Thanks again.

 

I'd go even further and offer the time to bleed the clutch slave cylinder is *before* the clutch starts manifesting problems and the shifting deteriorates.

I had a car manifest wonky clutch action and crunching shifting that was cured by a brake and clutch fluid bleed. The brakes felt fine before and after. Thankfully the clutch was smooth and easy to engage and shifting was once again great.

The kicker is the fluid was only about 2.5 years old. The factory called for 2 year brake/clutch fluid flush/bleed services which I adhered to save this one time when I lost track of time.

 

FWIW on my 3rd clutch slave here at 70K miles. The car is not tracked, I don't drive like it is but rather like the old guy I am (becoming). Lots of city driving though. 'While you're in there' not a bad time to just swap it out for a new one if you even think it might be getting there, and in any event if there is a leak of any kind. Not a fun job to bleed but plenty of guidance above, the Mod MINI video, plus this just posted yesterday from FCPEuro, who guarantees all their parts for life don'tcha know...

 

Purchased a clutch slave from FCP as a backup last year. For which I'll be installing at the same time I do a complete flush/bleed. I just placed an order for another slave (from FCP), as another back up for my parts stash.

 

Thank you guys for all of your insight and valuable contribution!

A quick update on my recent brake fluid flush and clutch slave bleed.
Well, after checking my records I was long overdue for a fluid and flush = 5years @17,053mi to be exact.

After 4weekends of impending rain in the forecast and having purchased a couple of new clutch slaves, Schwaben pressure bleeder, 3qts DOT4 brake fluid, and a new reservoir tank many weeks ago; I finally had a rain free weekend and preformed the complete hydraulic fluid service.

After removing the screen from the old reservoir and drawing out the old fluid...

Helpful hint: 2wo small screw drivers - Gently pinch/push in and lift out the screen. Easy!




The first thing I discovered was the degraded condition of my 18.5y/o brake fluid reservoir. I wasn't surprised to say the least.


After reinstalling a new brake fluid tank, I proceeded to pressure flush the brake lines w/2.5qts DOT4 until the entire hydraulic lines ran crystal clear.

As my daily driver, I keep the underside of my Mini super clean. Right away, It was easily apparent to me that the clutch slave looked as though it had been replaced (within the last 8 years) at one time (w/Genuine), with absolutely no indication of aged failure or evidence of leaking. So I decided to forego replacing it and bled it (6oz), 'til it ran crystal clear.

Upon success - Since then I've put it through a 75mi test run. All I can say is - WOW - It finally feels like I got my Mini back! = Firm brake pedal and nary a problem shifting into any gear even after a spirited romp or brutal stop n' go.
It even seems like it gets better everytime I drive it.

Thanks again one and all!

 

Nice !
Since I didn't dare to do it, how did the clutch slave bleeding go? Was it as easy as for the brakes? (I mean after you managed to access it).

Also by any chance did you spot an unplugged connector left of the brake reservoir? I got one with red and blue wires, and still no clue if it's supposed to be plugged somewhere (though the car isn't complaining about it).

 

Following

 

Granted that brake fluid reservoir is in terrible condition. But the first thing I would have noticed was the condition of the brake fluid you removed from the fluid reservoir. That's some past its change by date fluid!

 

Since it was obvious to me that the clutch slave on my car was in noticable new(ish) condition and not leaking - therefore I saw no reason to replace it and go through the new replacement procedure. Bleeding the existing one on the car, with a pressure bleeder 4 or 5 times(@12psi) was super easy and painless.
Other than the brake level sensor connection that plugs into the lefthand side of the reservoir, I didn't see any other wires or connectors.
Perhaps the wires you discovered (if not for the reservoir), might it connect to the master cylinder?
I'm not sure.

Yes, to your point - The lovely shade of earthy brown fluid was glaringly obvious (if not embarrassing) to me after pulling the screen.
As a side note: Although it's been many years servicing the brakes and fluid bleed on my older cars; For some reason I was surprised to find the DOT4 fluid I recently used was water clear.
I thought as I'd recall the brake fluid I used in the past was just a few shades lighter than ginger ale or 7-Up. (?)
Perhaps it maybe indicative of grade or brand...
​​​​​

 

@Fradow - By chance does the wire connector in question look anything like the one pictured below?

 

Unfortunately it does not. If I'm not mistaken that one is for the brake booster, and I'm pretty sure you or the car would notice if it was left unplugged.

The one I have unplugged looks like this (sorry, I should have put the picture in the previous message):