Datsun Roadster Forum-311s.org

Is the brake pedal at the same height as the clutch pedal?
On my 510 master I had to cut the threaded adjustable rod to get the correct pumping action on the master. If you look at the old OEM rod, the new rod should be about that same length and result in the pedal being the correct height and the master working correctly.
Proceed carefully as that was just my experience!

Linda

This is probably just wording, but I think that I should check. My suggestion was not to check that the pads are centered but that the caliper is centered on the rotor. It is quick and easy to do, and if it is not centered one pad could rub constantly generating heat between uses while the other will not touch except in use.

C.Costine. Yes, that is what I understood you to mean. I have jacked up the front of the car and spun the frt tires when the brakes have had a chance to cool to ambient temperature. A visual check shows the pads are very close to the rotors but have no actual contact when cool. The caliper therefor seems to be centered over the rotor. I assembled the calipers with the identical shim configuration that was is place on the old assemblies.
Linda, the brake pedal height is slightly higher than the clutch pedal. The master cylinder seems to be an OEM type and not a 510 M/C as there are no adapters on the fittings. Therefor the rod length should be correct im assuming. I cant be certain on the M/C as it is not stamped with a manufacturers logo. (Nabco or Tokiko are the most common I believe). The stamping only says "A 3/4" on one side and "AB-02" on the other. It is also stamped "2-J" on the end. Can anybody decipher those markings?

Can’t help with the numbers, maybe try an internet google search or ebay and see if there is a description.
On the rod , it has to be correct in order to get the push and the full release. Ascertaining that it is functioning correctly is roughly possible by having the pedal at the same height, assuming the clutch pedal is correct. If you have a spare rod you could experiment with making it fit to have the pedals even and see how it works. As mentioned I had to cut the rod to allow that to happen. It was years ago so I don’t know how much, but just threading the rod caused interference with the pedal with the 510 master. It was not plug and play, plus of course you need the adapter.
Does the rod on your brake master have threads or is it solid?
Linda

Linda. It is threaded. Currently is adjusted to its limit. (threaded so that the rod is as far toward the brake pedal as possible).

Linda. It is threaded. Currently is adjusted to its limit. (threaded so that the rod is as far toward the brake pedal as possible).

That is my point. It may be the wrong size, needs to be trimmed. I recall despite adjusting it, it was wrong.
BUT that was my experience with a 510 master. Get some confirmation first.
Linda

I finally removed and disassembled the master cylinder even though it reportedly was rebuilt just prior to my purchase of the car. I am running out of ideas on how to remedy the front brake symptoms ive been experiencing. I had a rebuild kit on the shelf that I had ordered from Ross that is the correct part number for an OEM style master. Allthough the kit parts were similar, they were not correct for whatever aftermarket master has wound up on my car. As stated in an earlier post, the master is not stamped Nabco or Tokiko so I suspected that I might run into this problem. On a good note, the master DOES seem to have been recently rebuilt as all components look to be in fine shape. The downside is, I have no idea who manufactured the master or how to order a rebuild kit if I ever need one. Also, I now know that a rebuild is not going to solve my ongoing problem. My next attempt at a solution will be to adjust the push rod length as suggested by Linda. Fingers crossed. A google search of the actual stampings on my master turned up nothing but some replacement parts for a commercial refridgeration unit. Hmmm...…...maybe I can modify.

Here is pic of the push rod on the brake master. Note that it is threaded, and you can see that it has been trimmed, because it was too long and not matching the length of the Roadster push rod and also pedal was not at height of clutch pedal. If you can get an approximate measurement of the old Roadster push rod, or even feel like swapping it in, that might work. Others have swapped in the old R push rod.
If you need a bigger pic let me know
Linda

Sorry tech difficulties. Not the best pic to see the push rod without dismantling, but hope you get the idea

Linda, your suggestion may just have paid off. I shortened the push rod and adjusted the pedal height to match the clutch pedal . A short test drive with no problems. A scheduled longer test drive this morning was delayed by a dead battery because I failed to notice that my tinkering with the pedal height resulted in the brake light switch no longer making contact. (SIGH) Hook up battery charger and make another pot of coffee and adjust brake switch location. Just returned from a trip to town (16 mile round trip) with no pad drag and no overheating of caliper assemblies. Fingers crossed that the mystery has been solved. Now Im left to ponder why this was not a problem BEFORE I did the brake job. The old pads I removed were reasonably new but I suppose worn enough to not drag on the rotor even though the master was not allowing full retraction. Im not gonna loos sleep over it but my OCD doesn't like unanswered mysteries. :{

Ha Ha, I think you’ve got it! I am slightly annoyed though, that the gurus on the board, (and you know who you are), did not step forward to provide the info sooner, or even reinforce trying the idea. Seems like some time wasted. There is a stay at home order, so no reason not to contribute, Ted!
(I pick on Ted because he deserves it )
Anyway, same info holds for the clutch master, the push rod has to be the right length, so keep those old Roadster push rods...
Buried in the archives somewhere is this info, which encourages searching while you are waiting too.
Alright, enjoy the ride and ,maybe take a pic or two

Linda

Linda, on the bright side, ive learned a lot of new info about our cars by going through all the possibilities and trying the various suggestions made by our generous members. Ive done several simple brake jobs on my roadsters over the years but never a deep dive into the system before. Wiki was helpful but ultimately it was member suggestions that taught me the most. I really should find a photo storage site so that I can contribute some photos but have not taken the time to do so. Any recommendations on a third party photo storage site that works well with 311.org? Im a tech caveman so simple is better. BTW, why cant we just load photos from our devices?

You do not need to use a 3rd party hosting, and you can load photos from your device directly to the forum. Go below the "post reply" and you will see an "Attachments" tab.
Select "add files" and go from there.

test

Thanks notoptoy.

Nice looking ride!