[sstteevvee]

Hi guys.

I've had brake dramas with my 83 1l zook for friggin ages an i'm almost at my wits end and i need some help.

Some background
Its drums all round and a non-boosted cylinder.

The dramas started happening after the original master cylinder shat itself and started pissing brake fluid everywhere. The new replacement cylinder sourced from a auto shop here in perth struggled to bring the brake pedal off the floor. The "pressure" point in the brakes was nearly at the firewall and would only come good with pumping but would instantly go back to the floor once you didnt pump.

After much stuffing around we bit the bullet and bought another new cylinder from the suzistore. This seemed to solve the issue however the natural end of stroke for this cylinder was wayyyyy higher than the clutch and accelerator pedals so after getting a decent "pressure" point we decided to bend the metal angle that the brake switch sits on in order to make the brake pedal sit level with the clutch when it wasn't being pushed. So this obviously means that the cylinder is not able to complete its full designated stroke but we thought this is ok as there is no pressure on the pedal until you push it to the take up point.

The problem we're having now is that because the take up point is close to the 'new' end of stroke, the brake pedal pressure point has pushed itself up on 2 different occasions applying pressure to where the brake light switch sits meaning there is constant pressure on the brakes. The roadside fix of pulling the brake pedal up bending the brake light switch up a bit sees the take up point drop straight back to the floor again, requiring pumping to get a confident brake feel which like before disapears to the floor again when you go to touch the brakes again.

So what do i need to do? Does the brake master cylinder need its full stroke to operate correctly? HAve i got the wrong cylinder (again)? Or is a slave cylinder causing me the dramas?

Really appreciate any help or suggestions on this one guys,
Thanks!!
Steve

[303zuke]

If you've bought a Master Cylinder from Suzistore with the part number 51100-80760M, this is a Maruti part for a 1.0lt with front disc brakes. These have a residual pressure valve in the front circuit for the disc calipers that will wreak havoc with getting the shoes in front drums to release.

The master cylinder you need for front drum brakes is Genuine P/n 51100-80010, but I doubt you'd get one now from Suzuki. I see Suzistore don't list them. Your Maruti M/C can be identified with the fluid reservior being common to both inlets on the top of the cyl. The M/C you need has the reservior over the front end of the cyl (rear brake circuit) with a pipe running back to the inlet near firewall (front brake circuit). I can post a pic if I dig one out.

If you can't find the proper cylinder new, you can get the internals to rebuild your original. Otherwise, bite the bullet and upgrade to front discs, as you have a perfectly new Mast Cyl for the application!

[royce]

Drum brake master cylinders have the residual pressure valve, not disc and yes if you have a disc master youll have a lot of trouble keeping a brake pedal

First things first, stop stuffing around with the stops under the dash, if the master cylinder doesnt release all the way it wont vent to the resivour and will hold the brakes on

Put it all back to normal, bleed it all and then using proper brake hose clamps clamp the flex lines under the master cylinder, if you have a good pedal move along to the flex hoses at the diff and try again, if its still tight remove one clamp at a time, checking the pedal for each one till it goes bad, rebleed that wheel and check its adjsutment (2 adjsuters for each front wheel)

if it goes bad anywhere youve got air in it still

Or convert to Disc, its a lot nicer

[sstteevvee]

Thanks guys, i've taken a couple of pics to show you the cylinder and also where the brake pedal sits naturally. To be honest its a little dodgy to have the pedal sitting there because as you can sorta see in my dodgy photo its wayyyy higher than the accelerator and it feels like you have to lift your leg a mile before you can get on the brakes. Especially considering its a 1L and the accelerator is down 90% of the time.






This pic is from the trans tunnel looking toward the door. You can see how low the accelerator is in comparison the the brake pedal

[royce]

is the pushrod going all the way into the master cylinder or is it adjustable?

[sstteevvee]

The only adjustment that i can see is at the far end at the brake pedal bracket. There is maybe an inch of thread which can adjust the 'tang?' (or U shaped bracket), position on the rod. This has been threaded as far to the cylinder body as possible but the pedal still sits that high

[sstteevvee]

So just to confirm can anyone tell me if this is the right master cylinder for the front drum brakes?

[sstteevvee]

Bump. Any ideas?

[sstteevvee]

Anyone? Even if someone can identify if its a disk or drum cylinder that'd be a huge help

[303zuke]

303zuke wrote:

You've bought a Master Cylinder from Suzistore with the part number 51100-80760M, this is a Maruti part for a 1.0lt with front disc brakes.

Your pic even shows "Made in India" cast in the side! All Marutis had front discs.

Your original Master Cylinder for drum brakes should have looked like this:

[sstteevvee]

Thanks heaps for that 303. I'll go outside tomorrow and grab a pic of the first new one we bought. Looks exactly like that one you pictured, although the reservoir was on the other side when we first got it and had to swap it around because it hit the firewall. Anyway before I go swapping it over I'll post a pic up. We were having issues with that one having a spongy pedal but I've since replaced the front shoes so u never know.

Thanks again, really wanna get this sorted as it's off the road till it is.

[sstteevvee]

OK so i went and got some pics







I've measured the pushrod because we had absolutely NO luck in getting a decent pedal from this thing. It was always near the floor and would only come up with pumping. I know this is a sign of air in the system but we honestly bled the s*&t out of it and even took it to a mech who said that he just couldn't get it any better. However, i'm more enclined to listen to you guys as you would def have more info on zook than he did.

Oh and thats the cap from the original cylinder as that one just had a normal one or a different plug from memory.

[Scrawny]

Do you still have the original one you first took off? Did you compare pushrod lengths? If you still have it and they are different you could try swapping to see if this helps. What do you use to bleed the system? I've always found full drum systems can be a real pain to get all the air out, manual bleeding seems to work best tho.

[sstteevvee]

Unfortunately i dont have the original one, it didn't make it through a shed clean out. Apparently it was about 20mm longer though, so i'm not sure what the go is there?

303zuke would you be able to measure the pushrod from the same position i have on the one you have there? Would be greatly appreciated!

Oh and its being bled manually, normally with 2 people so one can be at the pedal and the other can be at the nipple opening and closing as needed.

[zookz]

Hey I have an original one to suit in good condition. Pm me.

[303zuke]

sstteevvee wrote:

Unfortunately i dont have the original one, it didn't make it through a shed clean out. Apparently it was about 20mm longer though, so i'm not sure what the go is there?

303zuke would you be able to measure the pushrod from the same position i have on the one you have there? Would be greatly appreciated!

I couldn't find a technical reference listing the proper length of the pushrod, or even a range of measurements. The one I have here is 111mm from firewall mounting face to centreline of clevis pin. This is also the same distance I have on a Brake Boosted M/C, so I guess it must be right-ish.

There is a measurement to adjust the length for correct operation, but it is for the assembled length for one of the two pistons, which then sets the location of the pushrod.

[sstteevvee]

So the saga continues

I managed to get an original master cylinder as the one pictured above and put a rebuild kit through it.

Now i'm having issues again getting a good brake pedal. I've bled at least 1L - 2L of brake fluid through the system and i still seem to be getting small air bubbles coming through the nipples on the front brakes.

The pedal will almost hit the firewall and will only come up once its been pumped a couple of times. If i clamp both flexi hoses coming out of the master cylinder the pedal is rock solid, it doesn't move. If i remove either clamp the pedal goes down to about half way. The same thing happens if i only clamp the flexi line at the back diff. Then if i only clamp the flexi going to the front brakes the pedal goes a bit past half way. With no clamps the pedal goes to the floor.

It doesn't seem to have a leak because if the pedal is pumped and held down it won't move. But after the amount of bleeding i've done i'm starting to think that air is being introduced somewhere.

After a good 4+ hrs its got me stuffed. I've tried bleeding with two people, one pumping the pedal, the other opening the nipple, then closing, then raise the pedal and repeat. I've also tried the one man technique of using a line into a bottle with fluid in it and using the liquid as a seal, then opening the nipple and pumping. Nothing seems to be working

If anyone has any suggestions i'd be grateful!!

[royce]

adjsut your shoes till you think they are too tight, I found they work best at can just turn the drum with one hand

dont forget the front also has 2 adjusters per wheel