olsver

Member

• Aug 20, 2018

• #1

My drum brakes have lots of power on the first use (after being parked overnight) but then are less effective therein (without getting worse over time). On the first use they lock up easily with a hard push of the brake. Brake force is even on all wheels according to MOT and is strong enough to pass but not good for emergency stops.

I have tried the following:

• new shoes / springs
• new flex tubing
• new brake lines (just because they were shiny)
  
• bleeding
• new booster
• adjusting all the brake adjusters till they grip tight and then releasing 1/4 turn.
• checked for vacuum leaks

Could it be the vacuum storage chamber thing (not sure what it is called)?

 

Bobsticle

De Villes Advocaat

• Aug 20, 2018

• #2

Brakes work better when stood overnight as the drum oxidises. One good stab and your back to shiny iron.
It could be something as simple as uneven drum faces. That’s the problem with brakes. Each item is dependent on all the others.
I have gone from good brakes to only the off side front working in less than a week. I know the problem. All the rubbers on the slave cylinders are leaking on 18 month old units. It’s s constant fight to keep them in tip top condition and new parts don’t guarantee longevity.

 

Blackburn

Well-Known Member

• Aug 21, 2018

• #3

Take your drums off and put some chalk marks on the shoes, refit drum and spin whilst some one gently applies brake to see how much shoe making contact with the drum. What make of shoes do you have fitted?

 

R

rob1miles

Well-Known Member

• Aug 21, 2018

• #4

Agree with the above, just pulled the drums for annual check and adjust and suprised to see how variable and poor the shoe contact areas were. Filed down the high spots but disapointed as I tried hard to bed the shoes in with some very hard stops when the shoes and drums were new 2 years ago.

 

Extreedoc

Well-Known Member

• Aug 22, 2018

• #5

They do tend to grab at the first application of the brakes after having stood as Bobsticle has said. As long as they work ok the rest of the time...? You, however, seem to imply that you are less than satisfied with your brake performance? Which makes me wonder: is yours an 88 and does it have 10" single leading brakes up front? If it is also fitted with 750 tyres you might well struggle to stop it in an emergency stop situation because of the extra leverage of the bigger tyres. Sounds far-fetched I know but I have personal experience of this phenomenon. Is this the situation?

 

olsver

Member

• Aug 26, 2018

• #6

Thank you. I'm going to do that chalk trick and sand the shoes down. It is an 88" with 10" drums and larger 16" high walled tyres that don't easily lock up.

I have looked at the disk brake conversion but it seems a bit pricy for my budget at the moment.

 

Bobsticle

De Villes Advocaat

• Aug 27, 2018

• #7

Luckily mine have been swapped in the past for the 11 inch twin cylinder type so work very well when not leaking.

 

freelance

Well-Known Member

• Aug 27, 2018

• #8

Also your servo or vacuum pump could be getting tired