M/C fucked?

[lynchfourtwenty]

in the front yes, the rear no.. an the 280zx one wont fit without mods... however i think i might of fixed it... i disconnected the brake lines and ran some hoses into a soup can that was full of brake fluid.. then jus had my buddy pump while i held the hoses an kept the resivors full then i hooked the brake lines back up and ran those hoses from the bleeder valve into the resivor and i got alot of air out both ways.. i think it had so much air the rear resivor couldnt get fluid.. it would not go down at all an nothin came out of the bleeder valve.. now tons comes out the bleeder valve.. any way im gonna go bleed the rest of the brake system i will let you guys know how it goes

[slodat]

The reason I asked is, the ZX master cylinder (n/a or turbo) is for a disc/disc setup. You do not want to use that on a disc/drum truck. The drums need the residual pressure valve that is built in to the master cylinder.

 

fyi, the '79-'81 ZX master cylinders have the same mounting pattern as your stock 620 master cylinder. Should you ever convert the rear to disc.

[lynchfourtwenty]

cool cool. well good news!! my m/c isnt fucked.. bled all the brakes an yay it stops.. i jus need to rebleed them again an i think it'll be all good

[lynchfourtwenty]

hey can i gravity bleed my brakes??? what do i do jus open the valves on the calipers an drums an take the cap off the resivor and let it sit?? if so how long do i let it sit for??

[slodat]

I personally would never do that. Seems like it is just asking for air to get in the lines..

[Bugeye]

we gravity bleed at the dealership all the time, the problem is if you dont watch the master cylinder and it runs outta fluid, you have to start all over again

[lynchfourtwenty]

hmm whats the usual time it takes to effectively bleed the brakes that way?? the reason i wanna try it is because i dont have any tools to help me bleed the brakes and im often alone while workin on my truck.. sometimes like today i luck out an someone helps me...

[Bugeye]

it depends, we let them sit for an hour and constantly checked the mc, but these were HD chevy trucks

[lynchfourtwenty]

ok tomorrow thats what im going to do then.. i can do that alone easy and i dont even have to lift the truck up to doit..

[Bugeye]

just make sure you have something under the wheel to catch the fluid and only do one at a time

[lynchfourtwenty]

ok, is there any tale tale signs of when its done?

[Bugeye]

steady fluid coming out of the bleeder

[lynchfourtwenty]

10 4

[yello620]

Gravity bleeding works excellent for flushing the old dirty fluid out of the system, but doesn't work very well at getting small trapped air bubbles out of the system.

 

Open only one bleeder at a time, and do not let the master cylinder go empty.

 

And the 79-81 ZX master cylinder bolts right on with no problems. I have been running mine that way now for about 2 years with front disc and rear drum brakes. No problems whatsoever. Works great.

 

Jason

[lynchfourtwenty]

i see, the one i have is a 83 zx m/c.. didnt some of the older Z's have rear drum? i want to get discs on the rear.. but im broke right now so thats gotta wait till tax season or something.. not to mention i gotta find out if fineline or beebani or SOMEONE has any brackets for sale.. i have some sentra se-r rear calipers but i dont know if they would work because they use a pretty small rotor

[Z-train]

I just went thru four M/Cs that i had trying to find a re-buildable one.ALL had corrosion in the bore that honing wouldn't touch.

 

And no-one sells rebuilts-only new.Gee-i wonder why?

[SHADY280]

you can get a valve that bolts in line and it keeps the residual pressure in the rear lines so you can use the 280zx master, but get the early one instead. it may have a larger piston than the 620 unit, so it prolly gonna stop different, it may lock up easier.

[Z-train]

you can get a valve that bolts in line and it keeps the residual pressure in the rear lines so you can use the 280zx master, but get the early one instead. it may have a larger piston than the 620 unit, so it prolly gonna stop different, it may lock up easier.

 

 

The larger the bore,the more pedal effort required to stop.

[ppeters914]

yes 22$ an im gettin a new mc...

 

Only $22? :eek:

 

- brand and part number?

- what year?

- what size?

- and, most importantly, where?

[lynchfourtwenty]

i went to "costless" my local autoparts place an jus told em i wanted a 79 620 M/C it was $26 but i gave them my old one an they took 4 bux off.. its for front disc rear drum an its whatever the stock size for 79 is.. its a reman. an the one i have wasnt fucked it just needed a really good bleed job

[Z-train]

i went to "costless" my local autoparts place an jus told em i wanted a 79 620 M/C it was $26 but i gave them my old one an they took 4 bux off.. its for front disc rear drum an its whatever the stock size for 79 is.. its a reman. an the one i have wasnt fucked it just needed a really good bleed job

 

I can't get reman around here at all.And after all the bad ones,i know why-there is a corrosion issue when people don't flush systems regularly.If you get the rebuilt,i would pop it apart and check the bore to make sure it isn't pitted.If it is-the M/C could by-pass internally.