Hard brake pedal after rebuild ?

Series tree · May 9, 2020

So after three weeks of order the wrong size bolts for the master cylinder...turns out they are imperial. I bled the brakes today and upon trying out the brakes the pedal is really hard, it moves down maybe an inch or two with giving it some welly. The brakes work so in comparison to last time with the double pumping issue this seems more positive, note the snail cam adjusters have not been adjusted as it was too hot in my workshop today, the master cylinder rod is also as far back as it goes and i haven't adjusted this yet.

Obviously my ext job is to jack it up and do the snail cams but dies this sound like i am on the right track with things ...? Many thanks

Rodeo Joe · May 9, 2020

Is it non servo.......it will be a bit harder than you may be used to. If the brakes work ok but with a lot of pressure I'd look at the adjusters.
If its got a servo does it hold vacuum?

Series tree · May 9, 2020

Thank you for the response mate, yeah its non servo. New pads, cylinders, springs, master cylinder and pipes. Yeah fingers crossed its the adjusters, may have a crack at it tommorow

cornish rattler · May 9, 2020

Could be the rod an the master cylinder needs resetting if it's been messed with as when the brakes shoes start bedding in the rod on the master cylinder will need adjusting to suit but can take a while to get the brakes and master cylinder right and mite take a lot of miles till they are

Rodeo Joe · May 9, 2020

When you re built the drums did you give em a good whack with a hide mallet to settle everything down?

Blackburn · May 10, 2020

You need to set the master cylinder pushrod up as per the manual or recuperating valve will not work correctly.

Series tree · May 10, 2020

So today was a sucess, i removed the sensor above the brake so the pedal had a massive amount of distance it was now able to travel. Didn't seem to make a difference, i struggled to get one of the drums on even when the snail adjuster was at its lowest setting it was almost like the pads are just too wide for the drums. So i remembered seeing a guy on youtube having to trim down the metal plate on the pad where it meets the cylinder. So i did this minimally on every wheel and they all rotate freely and the brake feels powerful and firm.

cornish rattler · May 16, 2020

Series tree said:
So today was a sucess, i removed the sensor above the brake so the pedal had a massive amount of distance it was now able to travel. Didn't seem to make a difference, i struggled to get one of the drums on even when the snail adjuster was at its lowest setting it was almost like the pads are just too wide for the drums. So i remembered seeing a guy on youtube having to trim down the metal plate on the pad where it meets the cylinder. So i did this minimally on every wheel and they all rotate freely and the brake feels powerful and firm.

Did you back off the master cylinder rod first as the rod could have been pushing the cylinders out enough to stop the drum from going on even though the adjusters are fully backed off.

kermit_rr · May 16, 2020

cornish rattler said:
Did you back off the master cylinder rod first as the rod could have been pushing the cylinders out enough to stop the drum from going on even though the adjusters are fully backed off.

+1 if this isn't set right you'll have a world of problems

Series tree · May 16, 2020

The master cylinder rod was sat back as far as possible, like I say after I did this I was able to adjust each of the snail cams. I unbolted the sensor above the pedal and wound the screw within the pedal fully in so I had maximum travel

Series tree · May 16, 2020

Please tell this will be fine I have had these brakes apart so many times trying to do this I don't think I can bring myself to do take them apart again

Series tree · May 16, 2020

Posted a picture here to explain

cornish rattler · May 16, 2020

Series tree said:
Posted a picture here to explain

It looks right but just thought about something else if you have replaced the master cylinder did you check that both rods are the same as on some replacement master cylinder's the shank on the rods are longer than the originals so less adjustment on the rod and sometimes the rods are longer or shorter than the originals as well.

Series tree · May 17, 2020

I will have a look today my freind

Blackburn · May 17, 2020

With your brake pedal fully held up by the return spring the push rod should have a small gap between the piston of the cylinder and the pushrod . This is to ensure the piston is returning right out as there is a valve at the rear of the cylinder that only opens at that point.

Series tree · May 17, 2020

Is this what you mean the gap shown on the master cylinder ? To adjust this do i have to bleed/drain the system again ?

steve2286w · May 17, 2020

No bleeding required

Series tree · May 17, 2020

So i tried adjusting the master cylinder and it made the brakes lock up completely with no travel. Do i have the wrong master cylinder as i read in the manual the series 3 was fitted with two types. Alternatively the only thing i could think to do would be to cut more thread on the master cylinder rod ?

steve2286w · May 17, 2020

Adjusting it should release pressure on brakes by having the clearance in step 6 of the instruction , have you adjusted it tighter perhaps

Series tree · May 17, 2020

Moved the nuts towards the front of the vehicle

Hard brake pedal after rebuild ?

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