ausmini
https://www.ausmini.com/forums/

Brakes won't bleed up
https://www.ausmini.com/forums/viewtopic.php?f=2&t=21350		 Page 1 of 1
Author:  richarde [ Thu Aug 10, 2006 10:21 pm ]
Post subject:  Brakes won't bleed up
I have just finished reinstalling the brake master cylinder on my '76 clubby after overhauling it and am having problems.

I have been doing a bit of work on the brakes recently so i will start at the start:

My car has drums all round and the brake booster is disconnected (it was like that when i got it and there is no spot on the manifold to connect it to)

I replaced both drums and both sets of shoes on the front of the car because the car was pulling to one side and one of the drums appeared to be machined crooked. This made the brakes stop pulling as much, although the car still seems a bit unstable under brakes - don't know if this is normal or not. I adjusted all the brakes up after doing this.

I then decided that maybe the instability that the car seemed to have was from the rear brakes not working correctly. I tried bleeding the brakes to check for blocked hoses. The bleeding method i tried was pumping the brakes up then loosening the bleed screw to let the fluid out. i found that this didn't work on the rear brakes. I thought that the hoses were probably blocked so i replaced one and tried bleeding the brakes up. I tried the method that it says in my manual - open the valve, slowly push pedal to floor, close valve, release pedal and repeat. This seemed to work, but the brakes pedal never seemed to come up properly. I drove it like this for a bit but it was getting worse so i stopped.

After this the brakes seemed spongy and on hard braking the pedal would come very close to reaching the floor. If i travelled at about 80 or so and rested my foot on the brake pedal lightly for a bit then pushed it down i could get the pedal to hit the floor. From this i surmised that the master cylinder needed an overhaul.

I overhauled the master cylinder and replaced it, then bled all the brakes back up until clean fluid came through at the wheels. Again, the brakes didn't bleed up properly. The problem is the same as before - the brakes engage far too low (about 70% of the way down) and the pedal is spongy. The brakes can be pumped up a small amount and get firmer. The problem with resting my foot on the brake then braking hard and hitting to floor seems to have gone away now.

At no point has the brake system lost fluid (not noticeably anyway)

I was thinking of adjusting the brakes at the wheels again in case anything has moved or changed, but i am sure that there is something else wrong.

Other than that, my suspicion is beginning to fall on the pressure regulating valve, mostly because i am kind of at a dead end as to what else it could be.

Does anyone have any ideas?
Author:  TheMiniMan [ Thu Aug 10, 2006 10:50 pm ]
Post subject: 
Go back & """UN-ADJUST""" the """FRONT""" brakes,, (leave the backs adjusted up) ,then bleed the whole lot of em (all 4 wheels) again---> BUT!!! just let em all drip/gravity bleed,,,have a cuppa & keep an eye on the resovoire so it doesn`t run dry. lock up all the nipples ---> then adjust up the fronts & try the peddle after the second press they should all be sweet as a nut.

any dramas after that then means you have other dramas :-)
Author:  aussie [ Thu Aug 10, 2006 10:55 pm ]
Post subject: 
ive had EXACTLY the same problem, trying to set up the drums on my project. im really keen to find out what to do, im thinking about just taking the car to a mechanic/brake place :?
Author:  richarde [ Thu Aug 10, 2006 11:16 pm ]
Post subject: 
why would you take it to a brake place when TheMiniMan is right here? :lol:

Thanks MiniMan, I will let you know how i go when i get time to try it (going camping for most of the weekend)
Author:  aussie [ Fri Aug 11, 2006 10:32 am ]
Post subject: 
richarde wrote:
why would you take it to a brake place when TheMiniMan is right here? :lol:

Thanks MiniMan, I will let you know how i go when i get time to try it (going camping for most of the weekend)


yea i posted that before I saw his post, shal give it a go - cheers :D
Author:  richarde [ Mon Aug 14, 2006 10:21 am ]
Post subject: 
Last night I bled the car brakes using the method MiniMan stated, although i made the minor adjustment of having a beer instead of a cuppa :D

The brakes are a lot better than they were before, although the pedal is only "taking" about 60% of the way down. I will try adjusting the rear brakes again when i get time, as i am not sure if i adjusted them correctly.

I have also found that if i brake hard then the pedal hits the floor before the tyres lock up and I can pump up the brake pedal a bit.

So, there must still be some air somewhere in the system. I was thinking of jacking up the back of the car and then re-bleeding the back, in case the air is trapped somewhere in or near the pressure reducing valve near the back. Does anyone know of any places in Mini brake systems where air can get trapped, or how to get it out?

I have also heard that the air will sometimes tend to work its way out and bubble up into the master cylinder, depending on where it is in the brake system
Author:  aussie [ Tue Sep 19, 2006 6:17 pm ]
Post subject: 
Well for me it turned out i had a few more issues than just the brakes - i had to clean out the master cylinder and replace both rear brake cylinders. so after so many hours of frustration we finally solved the problem :D
Author:  Mick [ Tue Sep 19, 2006 6:29 pm ]
Post subject: 
Mini brakes are almost a good enough reason to ride a bike instead.....
Author:  Morris 1100 [ Tue Sep 19, 2006 6:37 pm ]
Post subject: 
My tip is don't muck around with old bits.
There is no point in spending hours trying to bleed the brakes when you could have spent that time replacing the rubbers in the wheel cylinders and replacing the brake hoses.

If you don't know how old the rubbers are you should replace them.
Author:  slinkey inc [ Tue Sep 19, 2006 7:01 pm ]
Post subject: 
I had the same, took it to a mechanic they wated a few hours all to find out the original master cylinder (tin type) was leaking so i got a new one from minisport, new cooper s one and it bled up easy no problems, I actaully didn't send the car in for brake bleeding, for tuning actaully and a few other things but that cost the most as they didn't know what they were doing, I shoudn't have asked them to do it..but oh well.

PS check after heavy brake use (push on and off a few time) for leakage into the caib in the footwell, you wont see it as it falls onto a shelf sort opf thing behined the pedals but feel, if it feels wet its most likely that your mast cylinder is leaking out the piston into the car!
Page 1 of 1 All times are UTC + 10 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/