Double brake - Brakes do not work like proper brakes !!!

[MAHINDRACJ4A]

hey guys

iv got a master cyl from a surf that i have put into the mahindra and to make the brakes work i have to push the pedal twice, if i push it once the brakes hardly work but then on the second push they work perfectly

what could be the problem i have bleeded the brakes about 4 times now maybe i need to do it agian a differant way perhaps ?

[turoa]

do you have discs or drums?

[mike]

where have you bled them? you need to bleed all high points, up by the master cyclinder (if youve removed that) and on any pips youve taken off or joins where air may have traveled to. Just keep at it.

Mike

[Furgus]

I had that problem in my S3 Landy & it was the master cylinder - didn't help the diagnosis when the new replacement one was farked too
Furgus

[MAHINDRACJ4A]

i just bleeded the four wheels

and i have drum front and rear

[MAHINDRACJ4A]

how can i bleed the master cyl ? my one does not have any bleeding points on the master

[turoa]

i just bleeded the four wheels

and i have drum front and rear

That might be your problem there

Drums require more fluid than discs so something with discs in the front will be pushing out less fluid

Correct me if im wrong. After the second pump is the pedal hard?

[Sadam_Husain]

Have you checked that all the brake shoes are adjusted up ok?

If the shoes arent adjusted properly you'll need to take a couple of pumps to bring the pedal up when braking.

[Jerry]

When you put the master cyl in did you bleed the cylinder first then the brakes

[MAHINDRACJ4A]

nope didn't bleed the master how do you do that ?

yes pedal goes hard on second pump and brakes work.....

brakes were working very good before so don't think it will be the brake shoes that need adjusting

[dazza85]

When you put the master cyl in did you bleed the cylinder first then the brakes

If not take the break lines off and bleed it first.
otherwise you just keep compressing the air in the cylinder and force more are through the system

I did mine holding a piece of tyre rubber over the 2 holes and got my wife to slowly pump the peddle the rubber lets the air & fluid out and does not let the air back in when you lift your foot.
then very slowly push the peddle down as you reconnect tubes

[mike]

I would say that saddam hit the nail on the head. is your handbrake good or has it a lot of travel. If they dont seem to be adjusting up by itself(read bad handbrake lots of travel) then take those rear drums off, adjust a few clicks on the adjuster and check the drum still slides over. If there is a lip on the drum then youll just have to hope they adjust up the final bit by themselves otherwise youll need to grind the lip off get it machined off.

Mike

[MAHINDRACJ4A]

hand brake is on the shaft so that works perfectly lol

[NJV6]

Master cylinder too small for 4 wheel drums.....?

[lilpigzuk]

i just bleeded the four wheels

and i have drum front and rear

That might be your problem there

Drums require more fluid than discs so something with discs in the front will be pushing out less fluid

Correct me if im wrong. After the second pump is the pedal hard?

ya reckon??
Had the same problem on lil pig after I put discs on rear end, thought it was the callipers need more fluid than the drums that caused it??

[MAHINDRACJ4A]

if disc set up needs more presure than drums then i have a master cyl from a surf disc front drum rear and my jeep has drum front drum rear so should have more than enough pressure ????

[tallsam66]

If after 2 pumps of the pedal you had a good hard pedal...ie not spongey there isnt air in the system.
Its more likely that the master cylinder isnt matched correctly to the brakes.The amount of fliud that is being put into the lines isnt enough to make the pistons move to put pressure on the pads & shoes to stop.Thats why when you pump it again it works.
Usually in a master cylinder designed for dics front & drum rear the cylinder is effectively 2 master cylinders in one.The reserervior is split in half & also the "pump" is split in half also.1 push of the pedal will deliver an amount of fluid to the disc & different amount to the shoes.Thats why its so important to have a master cylinder that matches the needs of the disc calipers & the slave cylinders.

[Jerry]

Hilux master cyl bore is 25mm, do you know what the size of the original one was, I know discs require more pressure, how warn are the bits inside the drums...maybe it needs a pump to push it to contact ?

[MAHINDRACJ4A]

The surf brake master cyl

the orignal old style jeep master cyl

[Mattman]

Drum brakes require a residual pressure valve in the master cylinder to maintain pressure to the wheel cylinders.

If pressure is not kept at the wheel cylinders then the springs will cause the shoes to fully retract which will mean that you need a greater amount of travel to get the shoes to touch the drums.

The valve is removable I think on the Hilux master cylinder, it will have one in the fitting on the master cylinder that runs to the rear brakes. Get another one off another cylinder and fit it to the front line.

The bigger question is why haven't you fitted front discs with all that power?

Matt.

[MAHINDRACJ4A]

do you have a picture of this valve thing tou are talking about ?

ha ha well just dont want to do the disc set up yet its still got the 3speed gearbox with a final drive of 1:1 and a diff of 5.88 so its never going to go too fast

aparenty been told by jeepers overseas that you must have big balls to do over 100km in a cj4a/cj3b jeep

[SupraLux]

Hilux master cyl bore is 25mm

Nope, 80-series cruiser is 25.4mm (1"), the Hilux is a 22mm (7/8") from memory.

And Mr T, I think its the other way around, drums use less fluid to activate than discs...

Personally, I'd be looking to double-check the bleeding of the system - maybe get a full-system pressure-bleed done at somewhere like Safe-R-Brakes...

Steve

[KiwiBacon]

Master cylinder too small for 4 wheel drums.....?

That's my suspicion too. Anyone know how the bore diameter compares?