1980 280zx brake master kit/replacement (510)

[nustad]

I'm running 280zx front discs and maxima rears on my 72' 510. My 1980 280zx master cylinder is leaking and I need a rebuild kit or replacement. I'm having a hard time finding a kit or new master.

 

Hoping someone can give me some direction or alternatives.

[nustad]

Anyone have a part number for a 7/8" master cylinder that will fit in stock 72' 510 location and work with f/r discs?

Any other tried and true options/ideas would be appreciated.

[Laecaon]

Rockauto

 

1983 Maxima. Lots of options, appears to be 7/8th

[nustad]

Looks like the 83 maxima has the horizontal bolt pattern. Would prefer stock vertical pattern.

[Laecaon]

How about a 81 200sx?

[nustad]

How about a 81 200sx?

Looks promising.

[datzenmike]

Get a 7/8 620 master and swap your rear residual valve in. For zx calipers a 15/16" master would be better. The S12 has 15/16" ...the mounting is wrong but the rebuild rubber seals might be the same.

[nustad]

I tried to look for a 15/16 kit and no luck.

 

Going to buy 7/8 for a 620. Thanks for the help.

 

Might send my zx master out for an A1 cardone repair and return. Any one have any luck with a service like this?

[nustad]

Get a 7/8 620 master and swap your rear residual valve in. For zx calipers a 15/16" master would be better. The S12 has 15/16" ...the mounting is wrong but the rebuild rubber seals might be the same.

Can not find any year 620 with a 7/8" master.

 

I did find a 7/8 for a 720. Did you mean 720?

[datzenmike]

shit, I meant the '78-'79 620... they were 13/16".

[nustad]

I returned the 13/16 thinking it was the wrong part.  Ordered the 720 7/8 but it looks like the bleeders are on the wrong side.  I'll try the 720 to see if there is an interference issue with the bleeders and clutch master.

 

Does anyone know the part number for the 7/8 master ermish sells?

[nustad]

Datzenmike, with my setup do I need to install the 280zx valve assembly?  I'm referring to the assembly mounted on the shock tower of the 510 that diverts fluid.  

[datzenmike]

The old front and rear lines just go to the new master...??

[nustad]

 

The old front and rear lines just go to the new master...??

I'm in the process of converting my front brakes to 280zx and my rear to maxima. I currently have the original 510 proportioning valve installed. Do I need to install the 280zx proportioning valve? I've read posts and DQ article that say I do but I think I've seen posts from you which made me question this.

[nustad]

"Proportioning valve? Most Datsuns don't have one. Front and rear bias is engineered at the factory by using smaller wheel cylinders at the back than the front or smaller calipers at the back than the front. The master cylinder is also designed to apply pressure to the fronts first ... this is why the fronts are at the back of the master. Because you have mixed and matched calipers the bias is totally out the door anyway." ~Datzenmike

[nustad]

Hmm... The 720 master has the rear port first and the front port last

 

Talking to myself now....

Going to try a 280z master. Will take the residual valves out of the zx and put them in the 280z.

[nustad]

Sent my zx master off to cardone to be rebuilt. Cost should be less than 60.

 

Going to research this more. There has got to be a good cheap alternative out there.

 

Ermish sells a replacement 7/8 i just need to figure out what it is off of.

[NaudiS4]

Ermish 7/8" BMC is a Beck Arnley 072-2694. it does not come with the push rod assembly and you can use the stock 3/4 from the 510 but will need to replace the concave washer that sandwiches the push rod ball with one off of a car that uses the same size BMC. This part is a direct replacement for the following:

 

72-73 240z

74 260z

75-78 280z

 

This info is from Ermish himself along with some Google searching. Hope it helps

[nustad]

Ermish 7/8" BMC is a Beck Arnley 072-2694. it does not come with the push rod assembly and you can use the stock 3/4 from the 510 but will need to replace the concave washer that sandwiches the push rod ball with one off of a car that uses the same size BMC. This part is a direct replacement for the following:

 

72-73 240z

74 260z

75-78 280z

 

This info is from Ermish himself along with some Google searching. Hope it helps

I appreciate the info.  This master is for a front disc/rear drum setup.  I don't see how it would work with my front/rear disc setup unless I added an proportioning valve.   

[Laecaon]

Im sticking to the 200sx suggestion, unless you found reason for not using it...

[nustad]

Im sticking to the 200sx suggestion, unless you found reason for not using it...

 

I didn't try this one.  I don't see any obvious differences from pics.  I will order one and see if it works (1980 200sx).  

[nustad]

Update:

I tried to send my 280zx 15/16" BMC to A1-Cardone but they no longer offer a return and rebuild service on this BMC.

 

Bought a 1980 200sx 7/8" BMC from rockauto for ~$32 shipped. It is new, EIS brand, with reservoirs. Fits in the stock 510 location with no issues. I'm still installing rear suspension/brakes so the final test is yet to come. Will update when tested.

[dscottdatsun]

Get a 7/8 620 master and swap your rear residual valve in. For zx calipers a 15/16" master would be better. The S12 has 15/16" ...the mounting is wrong but the rebuild rubber seals might be the same.

 

Would the rebuild kit for the S12 MC work for a ZX MC? The ZX rebuild kit (46011-P6525) is NLA. I got three and would like to rebuild them, or has some one had success in getting them rebuilt.

[KlassicMotion]

I know it's too late by now, but what I did with my 280zx front and rear disc setup with the use of the 15/16 master cylinder was to use the '79 280zx m.c. with the vertical mount, but I ordered an '82 280zx m.c. from the parts store for $40.  I used the new/rebuilt plungers inside the bore to rebuild my old m.c.

 

I've asked the same question about the proportioning valve;  the answer I got was that it is not a p.v. but just a junction block to activate the brake light switch.