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kcoke

Brake Master Cylinder 240z

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I have a 1971 Datsun 240z made in the month of April (4/71). I purchased a new Brake Maste Cylinder but it says it only works on 9/71 to like 73 i believe. It looks like it will work though the only difference is where the bleeders are on the cylinder. I cant find a new brake master cylinder for the early early 240z. Will this one work or do I have to find the early early one?

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Hi kcoke,

I just put up a similar post regarding rebuild parts. I'm going to NAPA tomorrow to get the parts. Wish to God that someone on the board would share their experiences with us. It would save some possible aggravation.

A '72+ master cylinder can be made to work. The brake lines may need to be rebent or new ones fabbed to hook up to it. It has been many years since I saw another 240 so I can't remember the differences were. I once bought a MC from AutoZone and after opening it realized that all remans are for the later Z's. If it's 7/8" bore it should really be no prob tho.

If you want to kep the car original then White Post Restorations can install a liner in your master cylinder. After that it is only a matter of getting a rebuild kit. I'll post again with the results of mypurchasing rebuild parts at NAPA. Comparing part #'s online seems to indicate that their parts for earlier Z's are correct. Automotive One in Orlando FL used to have all the kits for hydraulics on the early Z. I think they are going out of business tho. Bummer:(

http://www.whitepost.com

I was very pleased with the reline job they did. It took a couple weeks for turnaround but now my MC has eternal life as long as the rubber is replaced every ten years.

Jim

HLS30 23654 2/71 240Z

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Early master cylinders have the front and rear circuits reversed. The later master cylinders can be used on the early cars as long as you re-route the pipes from the master cylinder to the safety switch block to ensure that the front brakes are supplied by the circuit with the larger reservoir.

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As a follow up on my earlier post...

The latest news is that master cylinder rebuild kits for early 240Z MC's are not available from any of the major chains. Sure, they all list it but it might as well be on the NLA list. Hopefully this is temporary.

I am waiting 'til Monday when Raybestos and Beck Arnley are in the office to answer whether or not the parts are made any longer. My local Nissan dealer is also waiting until Monday for word on availability. Nissan wants $85 for the kit but if they have it...

Just thought I'd share this with my fellow first gen 240 owners. Hopefully Monday will see me with a kit on order.

Is anyone aware of Master cylinder kits available in other countries?? (For '69-8/71 240Z's)

post-12438-14150798592607_thumb.jpg

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Arne;

Do you know if there is a difference in the port sizes front to back? If there isn't a difference what would stop you from just swapping the reservoirs so the larger is going to the front either way? Then if my mind serves me right don’t the later master cylinders have the large reservoirs on both the front and rear?

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ZX cylinders have large reservoirs on both, I think the later S30 cylinders only have one large reservoir. The thought of swapping is intriguing, as my new car appears to have the later cylinder on it, without having moved the lines. I'll have to look into that.

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Update - my car definitely has the wrong cylinder on it, and it is connected wrong also. I'm a bit wary about simply swapping the reservoirs since the outlet ports on the wrong cylinder are distinctly marked with 'F' and 'R'. Looks like I need to add a master cylinder to my list of things to do. Which is too bad, as the wrong one on the car now is apparently brand new.

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Not to worry Arne. The MC you currently have is the cheapest and easiest to replace part. I'm only going to great lengths to keep some authenticity otherwise I'd use a '72 MC.

Now that I think of it the swept volume of each piston/circuit in the master cylinder is the same. Just change the reservoir. The reason for the larger reservoir is that as the pads wear a larger amount of fluid is required to fill the pistons in each caliper.

The idea of having the front brakes on the front circuit may allow for some minimal redundancy. If there is seepage past the forward seals the rears are there to provide backup even though they are on another (sep) circuit.

As long as the fluid is topped off it shouldn't matter which reservoir goes to front or back.

Of course this is all my opinion but it seems reasonable.

Jim

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Just thought I'd share what I've found regarding rebuild kits.

I got the LAST master cylinder kit in the USA today!!! It was $85.00 and purchased through Nissan. I tried Beck Arnley and Raybestos (aftermarket suppliers to parts stores) The early (69-8/71) master cylinder kits are no longer in production.

New MC's for first gen Z's go for $180-$270 depending on who's supplying. Interestingly NAPA offered to rebuild mine for me at a decent price. The 7/8" seals should be standard items. Special tooling might be required to unscrew the piston without marring the exterior. (This is probably a collet chucked in a lathe.) I'll post dimesions of the rubber seals once I get things apart in case anyone has access to a lathe or means of unscrewing the piston.

Jim

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Not to worry Arne. The MC you currently have is the cheapest and easiest to replace part. I'm only going to great lengths to keep some authenticity otherwise I'd use a '72 MC.
Considering the amazing originality of my red car, I'll likely still spring for the proper cylinder, rather than swap the reservoirs. for much the same reason as you.

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Please keep this thread updated as y'all find additional sources for these parts. Seems they are getting scarce and I will soon be needing to rebuild or source a master cylinder for my 7/70.

Thanks for the good info. to date!

Jim D.

"Zup" :bunny:

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The Brake Master Cylinder that I have the Reseviors look to be the same. (The fluid capacity is the same) Should I still swap the lines??

Keith

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Keith, I'm betting from the date of your car and the fact your cylinder is claimed to be for the later 240Zs, you will need to swap the lines when you connect it. But you could try to verify that. If the reservoirs are the same size check to see if there are any indications on the cylinder itself which port is for the front and which is for the rear. Then find the end of the block which has two out-going lines (one to each front brake). Connect that side to the port on your master cylinder marked as 'F' (if any). The half of the block that feeds the rear brakes will only have one line going to the rear, it splits into two lines at the rear of the car.

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Update - I received my new early master cylinder last week, direct from Nissan. My dealer said that there were (at that time) 5 in the US (4 in LA and 1 in TN). Now only 4 or less left...

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True, that is a very thorough post. But it's not very applicable to those of us who are trying to keep our cars original. There's lots of options available if we are modifying the cars, but only one correct answer for keeping them original.

FWIW, I have the ZX master on my yellow car, and even with stock brakes it works fine.

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I know that you guys were talking about keeping is stock but I thought I would throw out some "general" break info for anyone that might be doing a search.

Also ... Sentences 3 through 6 do say it all.

Matt-

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Hope this will help someone. I just got a early 71 240 z thats been setting in the garage since 1979. The break master cylinder was seized. I couldent get the pistons and springs out for the life of me.. Here is how i got them out - take out all the bleader screws get a big botttle of pine-sol and boil them for a couple hours.. then hit the bottom of the cylinder on some wood they will come out..

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Welcome to the forum, I'm interested why you used Pine-sol, was it just what you had on hand or is it good for other things?  The fact that the MC was seized means after you get it cleaned up it probably won't work for you anyway,  they use to sell a rebuild kit but the new MC are still pretty inexpensive so it's still easier and safer to grab a new one. Same goes for the wheel cylinders, the clutch MC and slave cylinder.

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