brakes not braking

manlikelandy · Aug 26, 2023

hello i got a 1962 109 what the brakes dont work. hase new shoos slave cylinders and all new brake pipes and a rebut master cylnder . no ristance on the pedel until the bottom and if i pump it there is less ristance as i found out the master cylinder is returning slowly brakes have bean bled and adjusted as mutch as i can get them. anybody come across this befor and know a fix? thanks

steve2286w · Aug 26, 2023

Does it have a servo, have you tested it my front brakes are same as the 109 with twin leading shoes.
is it running on the road to test, new shoes don’t stop that well till they bed in a bit
have you adjusted the master cylinder push rod
are springs fitted correctly
goes pedal go all way to bottom before it gets firm May be air in system or not adjusted properly
what do you mean by master cylinder returning slowly
manual says to clamp all 3 brake flexis and see if pedal firm then release one at a time to see which bit has air in system

kermit_rr · Aug 26, 2023

Sounds like air to me, but a slow master cylinder isn't right, need to find the cause of that

manlikelandy · Aug 27, 2023

steve2286w said:
Does it have a servo, have you tested it my front brakes are same as the 109 with twin leading shoes.
is it running on the road to test, new shoes don’t stop that well till they bed in a bit
have you adjusted the master cylinder push rod
are springs fitted correctly
goes pedal go all way to bottom before it gets firm May be air in system or not adjusted properly
what do you mean by master cylinder returning slowly
manual says to clamp all 3 brake flexis and see if pedal firm then release one at a time to see which bit has air in system

no servo i cant drive it on the road thanks to not able to afford the insurance the master cylinder rod i believe i got it set right i believe springs on the shoos are correct i put them on the same way thay came off. as for the master cylinder returning slowly there is about 1" of play in the pedal until i feel the rod on the master cylinder contact the piston on it and then if i press it down and then back up there will be 4 or 5" of play until it makes contact with the piston but if i waght a bit it returns to where it started. its strange will try to find 3 vice grips and clamp the lings and see if its aney better

steve2286w · Aug 27, 2023

Forge Steel Locking Pliers Set 3 Pieces - Screwfix

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something like these leaving a gap of about 6mm will be enough to clamp on without damage

if you pump pedal 5 times does pedal feel firm

have you got the 2 springs to return pedal back up

lynall · Aug 27, 2023

manlikelandy said:
hello i got a 1962 109 what the brakes don't work. has new shoes slave cylinders and all new brake pipes and a rebuilt master cylinder . no resistance on the pedal until the bottom and if i pump it there is less resistance as i found out the master cylinder is returning slowly brakes have bean bled and adjusted as much as i can get them. anybody come across this before and know a fix? thanks

Might pay to put some pics up of the brake backplate, especially the pipes etc, we will not critisise any wrong doing (we will of course take the pee!) but you might have made a silly mistake, like bleed nipple at the bottom/pipe to the top slave that sort of thing.
Has the master cylinder got a big nut shape on the end CB type? or is it just the plain and much easier to bleed and cheaper CV type?
Are you adjusting both shoes up?
Have you tried a pressure bleeder?

steve2286w · Aug 27, 2023

With the 3 clamps on , if poor pedal still need to look at the master cylinder again

Webley1991 · Aug 27, 2023

At least wrap a strip of rubber around the hose first before clamping locking pliers onto it.

How old are the flexi hoses themselves? Clamping off old ones can ruin them.

It is also possible that the rubber can break down inside the hoses and cause internal blockages.

manlikelandy · Aug 27, 2023

lynall said:
Might pay to put some pics up of the brake backplate, especially the pipes etc, we will not critisise any wrong doing (we will of course take the pee!) but you might have made a silly mistake, like bleed nipple at the bottom/pipe to the top slave that sort of thing.
Has the master cylinder got a big nut shape on the end CB type? or is it just the plain and much easier to bleed and cheaper CV type?
Are you adjusting both shoes up?
Have you tried a pressure bleeder?

i got the cb type master cylinder the brake pipes are plumed in the way the original ones where. i have adjusted each brake shue multiple times 2 adjusters on each corner if im correct. i dont have a preshure bleader.

manlikelandy · Aug 27, 2023

Webley1991 said:
At least wrap a strip of rubber around the hose first before clamping locking pliers onto it.

How old are the flexi hoses themselves? Clamping off old ones can ruin them.

It is also possible that the rubber can break down inside the hoses and cause internal blockages.

i have put new flexy lines on got some nice barmack ones befor thay closed

manlikelandy · Aug 27, 2023

steve2286w said:
With the 3 clamps on , if poor pedal still need to look at the master cylinder againView attachment 296337

will get some vice grips temmorow and try i had another look at the master cylinder rod adjustment and its at the end if the adjustment but still moving about 5mm until it makes contact with the piston inside gessing thats bad. i have one return spring to pull the peddle back up dont see where another one can go on unless you are tanking about the one on the clutch pedal if so yes got them on. the furst time i pump the pedal it goes almost to the bottom then goes firm naw but if i pump it agane it goes to the floor.

lynall · Aug 27, 2023

manlikelandy said:
i got the cb type master cylinder the brake pipes are plumed in the way the original ones where. i have adjusted each brake shue multiple times 2 adjusters on each corner if im correct. i dont have a preshure bleader.

I do not see how you can ever bleed that up with the nipple at the bottom?
I don't think you have a shoe adjustment issue, you still have air in the system.

You could always try and back bleed it with brake fluid in an oil can.

lynall · Aug 27, 2023

manlikelandy said:
will get some vice grips temmorow and try i had another look at the master cylinder rod adjustment and its at the end if the adjustment but still moving about 5mm until it makes contact with the piston inside gessing thats bad. i have one return spring to pull the peddle back up dont see where another one can go on unless you are tanking about the one on the clutch pedal if so yes got them on. the furst time i pump the pedal it goes almost to the bottom then goes firm naw but if i pump it agane it goes to the floor.

Ignore push rod to start with, set the pedal height via the stop bolt on the mcyl pedal box, then adjust push rod freeplay to a knatts cock, 1 or 2mm will be more than enough.

steve2286w · Aug 27, 2023

The pedal height needs to be set, that might help with correct rod adjustment , clearance should be 1.5mm
have you got access to the workshop manual, it’s online if you don’t have hard copy, I would double check with the pics in it as previous owner may have fitted things wrong
yes yours just has one spring mine has 2 being servo version my bad
might be bad pics but the pipes going in wheel cylinders one looks squashed and one a tight bend but may be bad pic
Halfords do a cheap one person bleed kit works well and less that a tenner

Europat Vizibleed Brake and Clutch Bleeding Kit | Halfords UK

Shop the latest Europat Vizibleed Brake and Clutch Bleeding Kit at Halfords UK

www.halfords.com

steve2286w · Aug 27, 2023

lynall said:
I do not see how you can ever bleed that up with the nipple at the bottom?
I don't think you have a shoe adjustment issue, you still have air in the system.

You could always try and back bleed it with brake fluid in an oil can.

On mine I swapped one side round to have it top but either way got good brakes
the adjusters need to be fully backed off before you bleed this allows the shoe springs to push the wheel cylinder pistons right back in pushing air into pipes where they come out of the nipple

is it correct that flexi goes direct into wheel cylinder

lynall · Aug 27, 2023

steve2286w said:
On mine I swapped one side round to have it top but either way got good brakes
the adjusters need to be fully backed off before you bleed this allows the shoe springs to push the wheel cylinder pistons right back in pushing air into pipes where they come out of the nipple

is it correct that flexi goes direct into wheel cylinder

I assume you mean it is rather than is it?

steve2286w · Aug 27, 2023

flexi on mine goes to bracket but may be different on earlier models, this is with the backplate rotated to get nipple near top

manlikelandy · Aug 27, 2023

steve2286w said:
The pedal height needs to be set, that might help with correct rod adjustment , clearance should be 1.5mm
have you got access to the workshop manual, it’s online if you don’t have hard copy, I would double check with the pics in it as previous owner may have fitted things wrong
yes yours just has one spring mine has 2 being servo version my bad
might be bad pics but the pipes going in wheel cylinders one looks squashed and one a tight bend but may be bad pic
Halfords do a cheap one person bleed kit works well and less that a tenner

Europat Vizibleed Brake and Clutch Bleeding Kit | Halfords UK

Shop the latest Europat Vizibleed Brake and Clutch Bleeding Kit at Halfords UK

www.halfords.com

yes i got the workshop manual for it sais that the pedal should be 158mm from the floor but its 148mm at the moment. and looking at the brake diagram it appears that the bleader is on the bottom cylinder too. will adjust the pedal temmorow but i dont think that will help. the copper pipe is not squashed and yes it hase a tight bend but i had to do that all bends where done with a pipe bender thay doo look squashed in the pitures was raining so i done it quickly.

manlikelandy · Aug 27, 2023

steve2286w said:
View attachment 296368

flexi on mine goes to bracket but may be different on earlier models, this is with the backplate rotated to get nipple near top

i think that is a s3 thing. 15 is the bleed nipple

Tall Ratbag · Aug 28, 2023

lynall said:
I do not see how you can ever bleed that up with the nipple at the bottom?
I don't think you have a shoe adjustment issue, you still have air in the system.

You could always try and back bleed it with brake fluid in an oil can.

The nipple being at the bottom is normal on these brakes on a 109, and is not actually a problem. The real problem with bleeding this type of brake is that an air bubble can get trapped in the wheel cylinders, and you have to do something that's a bit odd to deal with it.

If you take the drums off, adjust the brakes fully OFF with the adjusters on the back plate, and use a ratchet strap or similar to force the brake shoes fully back, you push the wheel cylinder pistons fully back, you force all the air and fluid back out of the cylinder, into the small bore piping,and then, these brakes bleed really easily. Obviously, when you put the drums back on, you then need to adjust the shoes back out in the normal way.

Quite often; even on here; you'll see people suggesting that you need to adjust the brakes fully on before bleeding; that just makes the air bubble in the wheel cylinder problem worse.

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