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Brake Bleed Issue
https://www.ausmini.com/forums/viewtopic.php?f=2&t=42898		 Page 1 of 1
Author:  dtorreal [ Thu Jun 12, 2008 8:57 pm ]
Post subject:  Brake Bleed Issue
Chaps

Hope someone can help. New to this MINI business so hoping someone can tell e what i'm doing wrong.

Have just finished checking my wheel cylinders and refit new shoes on my 68 deluxe. Installed some new drums and checked the brake hoses and all seems well.

Have installed everything, topped the brake fluid level on the master cylinder and began to pump yet i have noticed that there is no pressure gained on the brake pedal and after a few minutes not only do i not get a pressure gain on the pedal i also dont really get a drop in the fluids on the master cylinder.

Any ideas would be great.

Thanks
Author:  albino235 [ Thu Jun 12, 2008 9:00 pm ]
Post subject: 
Do you have any of the bleed nipples open?
If you do then I have no idea :lol:
Author:  doogie [ Thu Jun 12, 2008 9:00 pm ]
Post subject: 
Are you sure your flexable brake hoses are ok? Pump the syten up & crack the pipe into the master cylinder to see if fluid is coming out, then work your way done cracking every union in the brake system to see if theres fluid present.

In time you will find the problem, 9 out of 10 times it's the flexable hoses that have collapsed.

Doogie
Author:  Curly [ Thu Jun 12, 2008 11:00 pm ]
Post subject: 
Why won't this forum allow us to spell brake B-R-A-K-E :?:
Whenever it's written correctly in the edit screen format, it changes back automatically to BREAK when posted.
There's enough literacy problems on this forum without the site contributing as well :evil: Can one of the Mods have a go at fixing it please.
Author:  tinymorris1969 [ Thu Jun 12, 2008 11:06 pm ]
Post subject: 
mods have decided to play with the forum again so words like b r a k e become break. or like what happen the me with "the" becoming "the".


did you replace the wheel cylinders? if you did was there fluid coming out of the line while it was disconnected?. its a really wild guess but if there is no blockages a the seals in the master cylinder may be shot therefore not pushing the fluid through the system if that makes sense.
Author:  AEG163job [ Thu Jun 12, 2008 11:34 pm ]
Post subject: 
If the brayk master cylinder was working ok before, it is unlikely there's a problem with it now. If you have replaced all the wheel cylinders, it is likely all the lines are full of air. You should try bleeding the LH rear w/c first, then the RH rear, then LH front and lastly the drivers side RH front. Also, the top front w/c's can develop air locks, so you may have to loosen the connecting pipes to expel the air effectively.
Author:  dtorreal [ Thu Jun 12, 2008 11:53 pm ]
Post subject: 
So i checked the wheel cylinders. Didnt change them. Either way i did take them off so they would be full of air. And i have only dont the front wheels.

What is interesting is that the pedal never gets pressure. I pump for 5 minutes and then try to bleed and its like there in never any pressure. No air. Like as if there is a leak somewhere in the system
Author:  Hanra [ Fri Jun 13, 2008 6:56 am ]
Post subject: 
Please advise on your bleeding method.
Author:  sports850 [ Fri Jun 13, 2008 8:18 am ]
Post subject: 
How well was everything working before you changed the shoes and what have you touched (loosened hoses , changed brake switch , opened or changed anything in the brake hydraulic system?) . You say you checked the wheel cylinders , did you pull them apart and put kits through them or just visually check they weren't leaking etc ?
Author:  drmini in aust [ Fri Jun 13, 2008 8:40 am ]
Post subject: 
I have seen this problem before, the brake cylinder rubbers were old and sucked air in on the upstroke. But they didn't leak fluid out.
I've seen the same problem recently with a clutch slave cylinder.
In both cases, new rubbers fixed it. :wink:
Author:  dtorreal [ Fri Jun 13, 2008 9:08 am ]
Post subject: 
OK I think there might be some truth in the seals on the brake cylinder. I checked the O ring around the plastic top of my tin type brake cylinder as this came off with ease and on closer inspection PERISHED would not describe the condition of the rubber.

Wheel cylinder was inspected by a brake guy.

Lines could be an issue but they seemed fine.

I suppose i should look at both a master cylinder kit and some new hoses to cover my bases.
Author:  drmini in aust [ Fri Jun 13, 2008 9:10 am ]
Post subject: 
The seals I'm talking about are the slave cylinder cups.
These days it's not worth mucking about honing old wheel cylinders and fitting rubbers, new cylinders are cheap. :wink:
Author:  Mike_Byron [ Fri Jun 13, 2008 12:03 pm ]
Post subject: 
When your pumping the brake pedal - how do you do it ???

Furious and fast up and down pumps ???

Or slow and steady with a pause at the top and the bottom of each stroke.

Slow and steady is the way to go because brake fluid has a viscosity and its takes a few moments to be transferred. Once the lines are all full and primed that its at a constant pressure which simply is increased when you stomp on the brake.

Till then its one squeeze at a time with pauses top and bottom.

Mike
Author:  Curly [ Fri Jun 13, 2008 6:04 pm ]
Post subject: 
Curly wrote:
Why won't this forum allow us to spell brake B-R-A-K-E :?:
Whenever it's written correctly in the edit screen format, it changes back automatically to BREAK when posted.
There's enough literacy problems on this forum without the site contributing as well :evil: Can one of the Mods have a go at fixing it please.


Thanks for the fix, Mods :D
Now, how can we get Tinymorris (and others) to start using Standard English protocols such as capitals, punctuation and my favourite - the apostrophy :?:
Many of the posts on this forum don't reflect well on Mini owners or our education system. But we aren't all uneducated Yobs. :roll:

As for the brake bleeding problem, I agree with Mike - go at it slow and steady, and if you have a helper, get them to close the bleeder each time you reach the bottom of the pedal stroke and keep it closed until the pedal returns to the top. Open the bleeder only when the pedal is being depressed.
Author:  gafmo [ Fri Jun 13, 2008 8:53 pm ]
Post subject: 
i'd like to aliminantate two things here.
Can you please pull on the hand brake and do you feel a differance :idea:

when you adjust drum drakes did you feel a tight area and went for the soft area where the wheel spins freely
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