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Best Answer mattrsa , 03 April 2021 - 12:53 PM

Problem solved

 

 

Calipers were indeed on upside down. 

 

Not a mistake I will be making again. 

 

thanks for all the help and suggestions. I could kick myself wasting so much time. 

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#1 mattrsa

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Posted 28 March 2021 - 09:57 PM

Hi All

 

For the past 2 days I have been trying to get my brakes set up with no joy. I have replaced basically everything that can be replace apart from the solid brake lines.

 

Below are the detail 

 

1988 Mini Mayfair 

 

New Master Cylinder - yellow tag 

New brake control value

All new goodridge flexible lines. 

No visible leaks

 

I have bled the system with loads (about 500ml) of fluid through it to get the air out, and there does not appear to be any leaks. This was done with the help of a friend who has restored many classic cars and he is convinced there is no air in the system. 

We have bleed all the brakes (rear, front, as well as all connections on the master cylinder and brake control valve)

 

If I pump the pedal a good few times I will get pressure and the brake work but when I release the pedal that pressure goes and the pedal goes back to the floor.

 

It also appears that the brake pedal is sitting proud of the clutch pedal and if I lower it to the level of the clutch and then press the pedal the brake it seems to engage the brakes(as tested by trying to spin the discs). 

 

I have also tried using a single person brake bleed kit, the type that you attach to the wheel valve to pressurise the the system and when I do this there is good bite to the brakes. 

 

Any ideas. 

 

Apologies if the description is not that clear. Pulling my hair out on this one as I can't undertand why it is not working when basically every part is new. 

 

 

 

 



#2 MiniMadRacer

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Posted 28 March 2021 - 10:17 PM

Have you adjusted the rear shoes correctly?



#3 Cooperman

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Posted 28 March 2021 - 11:20 PM

As 'MMR' says, are the rear shoes correctly adjusted.

One other thing, make sure that when bleeding the rears, the bleed screws are opened before the pedal is pressed down. If this is not done, a pressure can build up before the pressure relief valve. The valve then stays closed and restricts fluid flow, and thus any air, to the rears. 

If the pedal 'pumps up', then it is definitely air in the system.



#4 MatthewsDad

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Posted 29 March 2021 - 06:58 AM

It is possible for air to enter the system via a connection that isn't quite tightened fully, but with no corresponding visible leak of fluid from the joint. Worth rechecking tightness of all the new joints.

#5 Tornado99

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Posted 29 March 2021 - 07:39 AM

As 'MMR' says, are the rear shoes correctly adjusted.
One other thing, make sure that when bleeding the rears, the bleed screws are opened before the pedal is pressed down. If this is not done, a pressure can build up before the pressure relief valve. The valve then stays closed and restricts fluid flow, and thus any air, to the rears.
If the pedal 'pumps up', then it is definitely air in the system.


Gravity bleed method would prevent that pressure build up before the relief valve, as no pedal movement is required. Worth a try, even if just on the rears. All you do is top up the reservoir, attach a clear hose to each bleeder, best to have the hose bend up in the middle to help trap bubbles, then free end in a catch bottle. Open bleeder enough to get a slow amount to come out. Then just keep checking MC level over ten or fifteen minutes, close bleeders and check performance.

#6 mattrsa

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Posted 29 March 2021 - 08:07 AM

thanks for all the replies guys. 

 

I have checked all connected to make sure they are tight but will check again. 

 

In work today but will have another go this afternoon/evening to see if I can get any joy and report back. 



#7 MiniMadRacer

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Posted 29 March 2021 - 12:11 PM

Back in the day I knew a BL mechanic who would adjust the rear brakes to lock the rear drums solid, then jack the front of the car up as high as he could and leave it overnight.. prob a total waste of time but his attitude was all the little bulbbles then overnight floated up to the master cylinder..



#8 mattrsa

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Posted 01 April 2021 - 02:54 PM

Update

 

Right well this is turning into a nightmare 

 

I have disconnected all the hoses and hard lines and then reconnected everything checking all connections as I worked my way from back to front. 

 

I have bled literally litres of fluid through the system, starting with the bleed nipples and then opening every connection on the master cylinder and brake control valve to bleed  them but am still not getting any pedal, however I do have brake when the pedal is pressed to the floor. 

 

I have even gone as far as switching the master cylinder back to the old one just in case the new one was faulty but that made not difference. 

 

Just as a recap I have replaced the master cylinder and the brake control value. 

I have double checked that all connections are tight. 

There are no visible leaks. 

 

The only thing which I have not replaced is the rear pistons but as I said they appear to be work and not leaking. 

 

I don't know where to go next



#9 sonscar

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Posted 01 April 2021 - 03:09 PM

At this point I would use air to blow out all the fluid from all nipples.Leave them open and go to bed(optional)Next day fill up the master cylinder and observe the bleed nipples.When fluid emerges let it run for a second or two then close it.Do not be tempted to press the pedal.Eventually all the nipples will be closed and the system full of fluid.

Couple of points that crop up all the time.Do you have the calipers with the nipples at the top?(do not be insulted by this)

The brake pedal should be substantially higher than the clutch(30mm?).It is vitally important that the brake pedal has free play,there is a hole at the beginning of the bore to let new fluid in and release old pressure.If this is not clearing you will be continuously pushing and pulling the same fluid.

Assume nothing is any good and start from the beginning as if it were a fresh install,I find this helps.

At this point you may very well have a good pedal.It never hurts to have a halper and use the Down/undo/tighten/up technique to polish the task off.Good luck,Steve..



#10 timmy850

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Posted 01 April 2021 - 03:32 PM

I’ve recently had a similar soft pedal after putting in rebuilt calipers. The front pads were loose when I poked them, which meant the first press of the pedal was taking up the slack, then the next press was holding pressure. Similar concept to the rear drum adjustment

Have you adjusted all the drums tight like suggested above? They should be tight enough to have some drag and not spin freely multiple times if you spin the wheel. Again, this is vitally important to getting a firm pedal

Another option is to clamp the rubber hoses and see if you can isolate the issue to one corner or end of the car

#11 cal844

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Posted 01 April 2021 - 03:43 PM

Is the car on disc brakes? If so clamp both of the flex lines on the front checking the pedal after clamping a line.

It may be that the front calipers are in the wrong side

#12 Revd

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Posted 02 April 2021 - 09:16 PM


I replaced everything except the pipe work and drums on my ‘87 last year. Not having a willing pedal pumper meant I relied on an eezibleed. My method which has not let me down, is to open all four corners to begin with. The theory being that air isn’t shuttled back and forth between front and rear circuits. Also a few pumps on the pedal before the eezibleed canister is empty. Then close the off-side front but keep the other three open, being close to the master cylinder the fluid flows out rather than pushing any air out the near-side front. Once I’ve got clear fluid and an absence of bubbles I switch to the conventional furthest corner first method. Pedal is solid, make sure you have plenty of fluid before you start-at least a couple of litres.

#13 mattrsa

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Posted 03 April 2021 - 12:53 PM   Best Answer

Problem solved

 

 

Calipers were indeed on upside down. 

 

Not a mistake I will be making again. 

 

thanks for all the help and suggestions. I could kick myself wasting so much time. 



#14 Maccmike8

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Posted 03 April 2021 - 04:24 PM

Result.



#15 cal844

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Posted 03 April 2021 - 04:34 PM

Good to hear buddy, an easy and inexpensive fix!




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