Brake Clevis

[seattlejester]

So I had this problem in the past, and I've just kind of ignored it. Time to finally address it. 

 

Has anyone found a source for the clevis for the brake pedal? I took one off of my clutch as the one I found and paid a lot for ended up being too short to reach around the metal plate of the pedal itself and I foolishly left it attached on my booster when I traded it in. I'm hoping for something a bit longer as well as there is a lot of slack before the brakes engage and I can't dial in the preload as it is maxed out on the threads.

 

If a source isn't available does anyone have recommendations on how to lengthen the clevis correctly? Should I lengthen the arms? Or should I weld on a coupler to the threaded side to extend the clevis length?

[NewZed]

Looks like they changed over the years.  #10?

 

Might be available from Nissan.

 

http://www.carpartsmanual.com/datsun/Z-1969-1978/brake/brake-clutch-pedal

 

https://www.courtesyparts.com/oem-parts/nissan-pin-clevis-46123h850a

[Miles]

Jegs, Summit and Speedway show a brake booster clevis 3/8-24 thread.  Not sure of thread type for the 240Z/280Z.

 

They also sell push rod extension kits.

 

I seem to recall (10 years ago) that the 240Z and 280s push rods were of different diameters and he clevis pins were different .  When I swapped in a 280Z booster into my 240Z I swapped the 240Z push rod into the 280Z booster so I could use the 240Z clevis.

 

My pedal has some slack, but the clevis is adjusted all the way out. If you find a way to lengthen the clevis post your solution here.

[seattlejester]

Thanks for the link NewZed I'll have to dig through the parts diagram and see if Nissan has something, but I think my terminology may be incorrect? The clevis I am referring to is:

https://zcardepot.com/collections/master-cylinder/products/copy-of-power-brake-booster-7-240z

The U-shaped pivot point? I think the last time I found it they called it a threaded hitch or something at the local hardware store.

 

After a lot of searching and for a ridiculous shipping charge I did find the clevis that looks identical to the Z car depot one a long time ago, but it was really short as in there was not very much room from the pivot to the thread, I think the brake was too thick for it to work in that application.

 

I am being lazy here, I'll get under the dash and make some measurements, as miles says my current setup is maxed out with only one thread showing past the clevis and I have a good 2-3 inches of dead pedal before I get to the brakes which can be kind of alarming. The solution is to either extend the arms of the piece, add a coupler for more threads at the bottom like a hybrid of the z car item and the current one, or find a longer push rod if the brake booster can swap the push rods about.

 

[seattlejester]

Just found this post.

I am running the 15/16 on a 240z booster. Curious I don't recall which I set the booster to if it was the early or the later spec. I'll do some diving and maybe pull the booster and see what would be involved with swapping the external pushrod if the internal one is correctly set.

 

[calZ]

McMaster has a pretty good selection of clevises if the pushrod switch doesn't work out. 

[NewZed]

My mistake, I was thinking clevis pin.

 

You could cut the rod in the middle and insert a tall nut, maybe.  Or put a bolt/screw through the back of the clevis and use the tall nut as an extension.  Spitballing...

 

Example - https://us.misumi-ec.com/vona2/detail/221005295770/?rid=rid3

 

Edited April 21, 2019 by NewZed

[seattlejester]

No, I've heard the pin called the clevis as well so I should have led with a picture of some sort.

 

That is not a bad idea. My original thought was to weld one of those to the backside of the clevis U thing itself. I wonder if there is enough length for the appropriate locking hardware to keep that all from rattling loose. 

 

I'll check mcmaster's catalog as well. I remember when I did this a while ago I looked up the grainger catalog and only found 1 option, maybe things have gotten a little better since then.

[Miles]

https://www.jegs.com/i/JEGS/555/631013/10002/-1

[seattlejester]

I believe ours are 8mm thread? 

 

Maybe it could be used with one of these.

http://www.linghunt.com/PartDOCS/B2409-X/B2409o14.html

 

I wish there was an 8mm stand off  which could save you the use of another lock nut. I suppose a tall nut (also found it mentioned as a studding nut) with all thread would be similar although it would require another lock compound on one side, maybe red locktite would do.

 

Clevis female rod end is apparently the correct name according to mcmaster

https://www.mcmaster.com/clevises

2448k48 seems like a longer variant of what I purchased before so it may be a viable commercial option.

 

[seattlejester]

Ok lessons learned.

 

The 43 mm clevis from mcmaster car is roughly 6mm longer than the stock one so it is good for a quarter inch or so more length if needed. 

 

Decided to grab a new 280z booster for the correct push rod. Might as well get the bigger booster I figured. Turns out, not the same bolt pattern in the early Z cars.

https://www.oreillyauto.com/detail/b/brakebest-brakes-4474/brake-systems-16456/brake-hydraulics-16513/power-brake-booster-11301/69bab478e25a/brakebest-power-brake-booster-remanufactured/535104/4566962/1976/nissan/280z?q=brake+booster&pos=1

Plus the interior side push rod that the clevis screws onto looked to be a 10mm thread.

 

The engine bay side push rods are indeed markedly different between the early years and the later years

The 280z ones seem to have almost 10mm of additional height on the rod cap/bolt. The one from the store sat with the tip protruding past the surface 22 or so mm.

 

I played with the cap/bolt on mine (71 240z) and was surprised to find there was almost a solid inch of adjustment.

The spacer on the booster that I believe comes with the master cylinder is roughly 9mm

And I set my nut to sit above the spacer another 13mm

 It takes a 7mm socket to undo and a pair of vice grips to hold the push rod which you can pull out a good deal. I believe pulling this can result in the reaction disc falling off in older boosters so be careful. Leaving the adjustment out and not bottomed out also requires a lock nut so be advised.

 

I set mine to match the store bought booster, which showed 22mm above the face of the booster. I figured this was pretty close to the 10mm number I read with the 10mm spacer that the master cylinder sits on, so I adjusted mine to the same. I then checked with the wheels jacked up to make sure they were rotating and grabbing when I applied the brake. With the correct adjustment on the engine side push rod I actually had to shorten the overall length of the interior push rod where the clevis is to make sure the car was releasing the brakes, so no long clevis required. Just an adjustment to the engine side booster push rod.

 

However be very careful about the adjustment. Make sure you run the car with the vacuum port hooked up and take all the tools to adjust it with you. (7mm socket and a vice grip in my case). If you have some room in your master cylyinder lines you can pull the master, pull the push rod and adjust it with a 7mm wrench or a socket with it hanging out a bit. I found this out on the side of the freeway. Make sure to check that the brakes are completely releasing. Even the slightly upgraded brakes on my car was enough to completely keep the car from moving, and if this happened dialing back the interior clevis rod end does not do anything, you will have to pull the master off the booster and shorten the engine side push rod. I'll have to go back and check, but pretty sure I ended up somewhere in the middle from my initial adjustment, there definitely is some tuning you can do here and it will give you a really really solid pedal with almost no dead zone if you get it right, get it wrong and you will either have your brakes solidly locked up or a huge dead pedal.