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Brake Pedal Not Returning Properly


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#1 E11OOT

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Posted 17 June 2008 - 09:35 AM

Hi,

The brake pedal on my mini is not returning fully so if i just lift off the break as usual they are still 10% applied. I have done a search and couldn't find anything, i do believe this is common problem, does anyone have some suggestions on how to fix this?

Thanks In Advance

Elliot

#2 Ethel

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Posted 17 June 2008 - 09:48 AM

What master cylinder do you have?

There's nothing physically connecting the push rod to the piston of the vertical cylinders. If it's that type look at the pedal itself and its return spring. It could just possibly be the stop washer in the end of the cylinder too.

#3 alexcrosse

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Posted 17 June 2008 - 09:49 AM

this has just happened to me with the master cylinder ive put on, rebuild time

ps. brake pedal doesnt have a return spring? its integral in the master cylinder isnt it?

Edited by alexcrosse, 17 June 2008 - 09:50 AM.


#4 Ethel

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Posted 17 June 2008 - 10:15 AM

I don't know about the horizontal cylinder - it may be moved to the under bonnet linkage. Vertical cylinders have a spring that's shared between the two pedals: the pedals are way too heavy for the spring in the cylinder.

#5 GraemeC

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Posted 17 June 2008 - 10:20 AM

Are you sure the pedal isn't returning properly or that the brake caliper pistons are sticking slightly? (Assuming disk brakes)

If the first then Ethel has pointed you in good directions. (Yes there is a return spring on the brake pedal, it wraps around the pedal shaft.)

If the second then it sounds like you calipers need a good overhaul.

#6 E11OOT

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Posted 17 June 2008 - 10:48 AM

Are you sure the pedal isn't returning properly or that the brake caliper pistons are sticking slightly? (Assuming disk brakes)

If the first then Ethel has pointed you in good directions. (Yes there is a return spring on the brake pedal, it wraps around the pedal shaft.)

If the second then it sounds like you calipers need a good overhaul.


discs are not sticking, if i depress the pedal then release the brakes are still slightly on, if i then push the pedal back up with my foot the brakes release completely.

#7 E11OOT

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Posted 17 June 2008 - 10:50 AM

not sure what type it has, maybe you can work it out from this picture...

Posted Image

#8 998dave

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Posted 17 June 2008 - 10:52 AM

rear brake springs could be a cause for not returning too, would feel like the handbrake dragging

#9 E11OOT

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Posted 17 June 2008 - 10:59 AM

rear brake springs could be a cause for not returning too, would feel like the handbrake dragging


handbrake doesn't drag, but i will look again when i get home.

Cheers

#10 alexcrosse

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Posted 17 June 2008 - 12:20 PM

you need to rebuild your master cylinder im affraid!

or another to replace it. The fluid isnt being allowd back into the reservoir, thats what is happening to mine (vertical).

do have a servo for sale that was working fine when i took it off, with master still attacked, easy swap.

#11 Ethel

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Posted 17 June 2008 - 12:32 PM

That's a horizontal cylinder. Disconnect the push rod on the cylinder from the pedal mechanism so you can see if the fault is in the pedal linkage. If the pedal moves freely I'd suspect the servo. It doesn't sound too major and may only need a strip and clean.

#12 alexcrosse

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Posted 17 June 2008 - 12:35 PM

mmm, my throttle pedal doesnt have a spring ethel, any idea where i can purrchase one from? did a search on sport and spares but with no evale. Only the clutch is sprung.

#13 E11OOT

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Posted 17 June 2008 - 12:40 PM

That's a horizontal cylinder. Disconnect the push rod on the cylinder from the pedal mechanism so you can see if the fault is in the pedal linkage. If the pedal moves freely I'd suspect the servo. It doesn't sound too major and may only need a strip and clean.


cheers will do.

thanks for everyones help so far!

#14 Ethel

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Posted 17 June 2008 - 12:45 PM

Do you mean your brake pedal Alex? The throttle pedal doesn't have one.

I did wonder, you started out with a horizontal cylinder I believe? I dunno if Moss or Minispares stock them. If not you may be able to rig something up with a spring from the scrappers or elsewhere. Something similar to the return spring on the pre verto clutch arm maybe?


Just a thought - I'm not sure that the return spring off the horizontal cylinder linkage isn't just the same spring that does both clutch 'n brake pedal on the vertical setup.

Edited by Ethel, 17 June 2008 - 12:48 PM.


#15 alexcrosse

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Posted 17 June 2008 - 12:48 PM

yer, sorry im talking carp, ment brake!

yer in the process of a conversion, minispares nor minisport do, ill check moss. Might just drill a hole through the pedal and rig up a spring.

cheers, al.




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