MK Brake Master Cylinder problem

[trublubiker]

Hi all,

I'm a new member and this is my first post. I'm a old fart on my fourth Patrol, an '86 SD233T Wagon.

I found this forum when I was searching for a Brake Master Cylinder kit. I figured that was what I needed 'coz my brake petal needs a couple of pumps to get some pressure. I'm not losing fluid so I figured I probably needed some new rubber seals on the piston.

I'd love to find a schematic for the Brake Master Cylinder and also some info on where I might get the kit.

Thanks

[NissanGQ4.2]

Hi mate, Welcome 2 the forum.

Can you post up an into in the intro section when you get a chance, You will find more members willing 2 reply 2 a question if an intro has been posted up.

Cheers

Todd

[pearcey]

G`day mate.
Before you start on the master check the rest of the system especially the linings if it has drum brakes.
Make sure the brakes are adjusted properly before you attack the master. With drum brakes they dont have to be too far out of adjustment before you have to pump the pedal.Also check for fluid under the wheel cylinder boots, If wet replace the cylinder rather than re kit it as the bore is more than likely pitted and honing only makes it worse. If any of the cylinders are wet this can be a sign that air can be drawn into the system every time you release the brake pedal. A Quick bleed at the suspect wheel may produce telltale bubbles. Hope this is of some help

[trublubiker]

Thanks pearcey


Will have a look.

[trublubiker]

Adjusted rear drum brakes and handbrake. Now have good pedal and handbrake, but only stopping on back brakes.

Not losing any fluid anywhere so my gut feeling is that the rubber rings on the master cylinder piston for the front brakes have perished. It would be a fair assumption as pretty much everything on the car is original.

Can pick up a master cylinder on-line and I'm wondering if it is an easy 'bolt on to the booster and bleed job'.

I haven't had the master cylinder off the car yet as I'm still driving it, very gently, and it stops quite well in my 50K town, so I don't know the significance of the 23.81mm Bore size mentioned in the listing. My Master cylinder seems to be the original, with 'Nissan' embossed on one side and 'Tokico' on the other side.

My model is a late '87 build, I think an MK, so if anyone knows the significance of the bore size I'd love to know.

[trublubiker]

I've just bought it so I hope it's OK.

[MQ MAD]

There just a unbolt and rebolt on the booster, fairly simple
Before you bought said suspect part, had you done a complete visual for any suspect leak/leaks/sepage ???
A shorty here had the dreaded brakes one pump,not the other syndrome
It was a bend in a line,(that ended up eventually breaking) few pumps hold pressure, then drop once pressure was released and tried again
Replacement brake line fixed that
Anywho you have the new master cylinder now,mite as well fit it,and do a full system bleed

[trublubiker]

There just a unbolt and rebolt on the booster, fairly simple
Before you bought said suspect part, had you done a complete visual for any suspect leak/leaks/sepage ???
A shorty here had the dreaded brakes one pump,not the other syndrome
It was a bend in a line,(that ended up eventually breaking) few pumps hold pressure, then drop once pressure was released and tried again
Replacement brake line fixed that
Anywho you have the new master cylinder now,mite as well fit it,and do a full system bleed

Thanks for the reply. Much appreciated.

I did crawl around and look at all slave cylinders, no leaks that I could see, plus I wasn't losing any fluid from the master cylinder.

The replacement arrived today so will fit tomorrow, get a 'pumper' to help with the bleed, and hope all goes well.

Thanks all for the helpful info and I will advise the outcome.

Cheers

[trublubiker]

Hi

I finished up getting the one man 'Vizibleed' and did the bleed by myself, starting with the rear N/S.

Just jacked up and removed the wheel for the slave cylinder I was working on and worked my way round the car.

After I'd done the rears I didn't have too much pedal, but after doing the long run on the front the pedal was pretty good and finished up great when I did the last bleed.

Thanks to all for the very helpful advice.

Cheers

Kevin

[ishie]

There just a unbolt and rebolt on the booster, fairly simple
Before you bought said suspect part, had you done a complete visual for any suspect leak/leaks/sepage ???
A shorty here had the dreaded brakes one pump,not the other syndrome
It was a bend in a line,(that ended up eventually breaking) few pumps hold pressure, then drop once pressure was released and tried again
Replacement brake line fixed that
Anywho you have the new master cylinder now,mite as well fit it,and do a full system bleed

i just wanna know where did you bought your brakes? i loss my brake yesterday and i dont know how to put it back :(

__________________
Emergency Brake Parts (http://www.jcwhitney.com/emergency-brake-parts/c15894j1s17.jcwx)

[Robo]

How is it booster makes rear brakes work but not front, can't bet he right problem.
Think a common problem with those old MK was a small disc falling off the brake booster assemble internally.
symptom very long soft peddle with obvious less brake affect. Gen manual describes this affect, experienced this twice on a MQ and MK.
Service the front end.
Extra good chance calliper piston seals are swollen and causing pistons to stick, not to mention full of rubbish and possible corrosion. these all happen with an ageing vehicle , not to worry.
Another cause is because the rear haven't been working properly for a while the front have been working overtime and could be glazed up.
again this requires attention, recon machining is a waste of time they are so cheap to replace with new ones these days. For the age of vehicle, it'a good chance their under size anyway.

And those old rubber brake lines will be adding to spongy peddle feel also. whether you think so or not.
new rubber after market copied from original at local brake specialist should be a reasonable price, and Teflon lines are an upgrade very worth while they don't bulge and as a result give a much firmer peddle, a little dearer but recon worth it and especially for towing are worth the extra few $, Teflon around $300+ for all 6.
You really do feel the upgrade with Teflon lines.
Fix em right and they might just save your life.
Cheers.

[trublubiker]

You misunderstood, it was a faulty master cylinder, not the booster.

As you are probably aware it is a twin system, and the piston that pumps to the front brakes wasn't working, so no front brakes.

Anyway mate, job done, problem fixed. I've now got good brakes. :thumbup:

[Robo]

Sorry, my mistake.
that's what happens speed reading, glancing over.
So forget the first two lines.
the rest still stands.
Maintance/repair tip for brakes anyway.
Cheers mate.