have power bled brakes a few times and still crap . the pedal is initially firm and can be compressed a bit .but if i hold my foot on it i can get it to continue toward floor . so has anyone heard of mc seals wearing internally and not the usual (fluid on the floor) out the back?

 

Hmmm. If your foot is going to the floor, the fluid is going SOMEWHERE. If you do this a few times, do you notice the fluid level getting lower, or air bubbling into the master cylinder reservoir?

 

that's what i was thinkin (WHERE's it goin) ? no fluid loss . but i did not look for bubbles . thx for the help . i'll try it .

 

take a look at the rubber brake lines also, i had a problem with the hydraulic clutch in my porsche where i would press the clutch pedal but the clutch wouldnt move, happened that one of the rubber lines would expand like a huge bubble when i pressed the pedal.

 

of seal failure where the fluid leaked from the master cylinder into the brake booster. It just gets sucked into the engine and burnt. I'd think that's what's happening to you.

Matt

 

Is the engine on or off when you do this?

 

exactly . it's on but no loss of fluid . it doesnt drop to the floor and i havent let it go all the way to floor but can assume it would . my mother in laws altima does this and is new . hers has much more initial pressure though. it does take force but i've never seen a car 's pedal keep going - normal?

 

Sounds like the master cylinder is bypassing internally, the fluid is pushing past the internal seals but not past the external ones. You either need to rebuild that one or buy a new one.....

 

let's say it got air in the abs unit , i may have let mc run too low on fluid when bleeding last yr. can this unit be bled ? i looked for bubbles and none . i did try to floor it and (good news ) it would not . it does pump up a bit better if i pump um a few times . is there a rebuild kit available for these mc's? and if air in abs am i f'd? thx for all replies .

 

I would suspect air in the ABS. I had this problem in my Camaro when I let all fluid drain out during a brake and line swap. I repeatedly pressure and pedal pump bled the brakes and then replaced the master cylinder but that did not help. I finally took it to a shop where they pressure bled five times. It was better but not great. The shop said they suspected a air bubble in the ABS which can be hard to get out. We pedal pump bled the brakes a few more times and finally got it back to normal.

 

thx ; i guess i'm a brake bleeding fool for a while !!

 

This may not work on the MINI as I understand the ABS unit needs to be "cycled" by a piece of equipment the dealer has.

 

dude.....

 

The Bentley manual states that the car needs to be connected to the dealer scan tool and the ABS put in a service mode for "proper" bleeding. That said, MANY folks have done full bleeds without this... but I know I let my reservoir run dry once, and suspect I have some air in there because I've been spongy ever since, after several flushes and bleeds... I may have to break down and pay for a dealer flush eventually.

I'm going to do one hardcore manual bleed with my son on the pedal and me on the bleeders, and see if that shakes loose whatever air is left in there... I usually use a Motive powerbleeder and that hasn't done it.

 

but many repair shops have the tools. FWIW, the AutoEnginuity SW with BMW extensionis can put the ABS system in "service mode" (actually it buzzes and clanks as it moves it's valves and pistons....)

Might want to take it out for a spin and get the ABS to engage (more than once) and do a bleed or two as well. Worth a try for sure.

Matt

 

Pretty easy to do this on gravel, ice, or snow, somewhat easy in the rain
on smooth roads.

 

Hmmmm..... this may be the thing that pushes me over the edge to buy AutoEngenuity...

 

On my 2003 MCS I let the reservoir run dry when I swapped my brakes. I filled the reservoir, bled the clutch, and bled the brakes. All was good, I guess I was lucky.

For some cars, I have read that the key has to be on, to activate the ABS, during the bleeding process. I do not know if that is a good process for the Mini but it might be worth investigating. I also like the thought of just getting the ABS to activate by driving and skidding. Then trying again to bleed the brakes.

 

And it's expensive for sure. I'm not that happy with it, the data logging is slow, but it's a lot less than the professional solutions....

Matt

 

Yeah, I know it's not perfect - I've read the critiques here - but given how deep I'm getting into DIY on the MINI, and given that I have some weird behavior that I want to diagnose, and given that now there's this ABS thing... It's probably worth the money for me. I'll probably add another datalogger later along with some dedicated probes (wideband, EGT, other temps).

Best deal I found was at bimmerzone.com. Ordered.

 

thx guys great idea to try and activate the abs then bleed . i will try it . now i gotta find some sand .....

 

You can drive over to my house next weekend and we can use my AutoEnginuity....

 

On modern ABS units, the factory or compatible scan tool is required to bleed the ABS. You can also activate the ABS by locking up the brake and causing a skid a few times. A wet road surface helps. I've done this on my other cars.

 

k wherwe you live?

 

Blimey,

So did you order the AutoEnginuity scan tool/software? I am intersted to see how you got on with the ABS activation with the tool and what the process involved.