Datsun Roadster Forum-311s.org

1970 1600, took for a short drive. Pulled it into the garage and parked. I always pull the emerg. brake handle to lock in place. When I went to drive it again, the handle would release as usual, but the brakes did not release. Any thread on this forum that I may have missed that can tell me what to look for to unlock my brakes? If not - does it require that I pull the wheels and drums and inspect? I can see the cable move back and forth from under the car when the handle is pulled back and lowered. Suggestions appreciated.

This diagram may be helpful as you work the issue. It's probably in the linkage mechanism somewhere and pulling the drum won't resolve it. Tension isn't being released on the wheel cylinder e-brake levers which is engaging the shoes on the drums. If it all checks out, then it's possible it is a bad wheel cylinder in which case you would need to pull the drums. Brian at Sin City Datsun sells reproduction wheel cylinders if it comes down to that.


https://www.carpartsmanual.com/datsun/s ... 6220000681

It sounds like the wheel cylinders are failing, it the cable moves to slack and the car will not move freely I would look at the wheel cylinders. You could probably loosen the rear brake adjustment and if that frees it up right away it would be a good bet that the wheel cylinders are going bad.
Dave

ThanX DCA21 and david - I'll check your suggestions next week when I can make time to fully inspect. Once I discover what is happening I will update the thread. ThanX again. Have a nice weekend.

So far: Rear axle on jack stands. Discovered the passenger side rear wheel will not spin. As stuck as stuck can be. Emergency brake works - as when I applied the emerg. brake my driver side rear tire will not move. Otherwise my drive side rear tire spins when emergency brake is off and not in gear. Removed both rear tires so I can see how both work more easily and can see the brake cylinder.

Questions as I've not done this before:
1) do I need to remove the brake drum to remove the brake cylinder? ie since the cylinder is taken off from the back side of the brake plate. Those shims look like a pain in the as... to get off. The brake drum on both rear wheels does not come off just by pulling off. (emerg brake is off and not in gear). So there must be some trick to getting the drum off - if I need to take it off.
2) do I need to bleed the entire brake system prior to pulling the brake cylinder or can I do some trick and put plastic wrap on the brake fluid resv. to keep most of the fluid it.
3) will removing the brake cylinder release the pressure that is keeping the tire/wheel from turning? Or do I need to do a complete disassemble of everything around that wheel to release the pressure.

suggestions welcome. ThanX Darrell

The way the brakes work is a hydraulic cylinder pushes outwards a fairly small amount against the brake shoes which are like half circles which then press against the drum... so if the cylinder is extended for any reason (hydraulic or mechanical) the drum will not come off, and it needs to to gain access. So, first examine how the mechanical and brake part works and see if it is hanging up. With the parking brake off there should be slack in the linkage. If that's not it, there is a brake shoe adjusting screw/bolt at the bottom of the backing plate that has a square head (often rounded off) that will back the brake shoes off the drum if you turn it counter clockwise. You may need a pair of vice grips to lock on and turn it, and it will take several turns but eventually that should relieve the tension on the shoes/drum allowing you to remove the drum. Be as nice to this adjuster square head as I said, they are often rounded off and should be engaged well so your tool/pliers etc are not spinning and rounding the head. Hitting the drum hard and repeatedly in several places with a RUBBER maillot can be very helpful as it vibrates things and loosens them, and after getting very hot from your drive I'd imagine things have tightened up a lot.

After you get it apart repost and we'll guide you based on what you find.

Thank you Greg. Good instructions. That wheel/drum does not move at all when the emerg. brake is off and not in gear. It is as tight as tight can be. I'll update once I am able to get the drum off. Should be able to get back to this by the weekend. Stay tuned.

At the top of each backing plate there is an adjuster for the emergency brake. It pushes the shoes against the drum so that the handle when pulled will press the shoes. You use the screw on the back side to move the shoes.

The screw adjuster has a square head. I use a 12 point or square socket, square is best. It is easy to strip off the corners if you use anything else. You can see if these will turn. They are often frozen.


This one has a broken stud.


Here you can see the part that presses on the shoes.

Thank you Curtis for the correction on the adjuster location... I've had an RX7 LSD with discs for many years and have not messed with stock brakes in quite awhile so, IT'S AT THE TOP!

The Pic above shows what I mean about the adjuster head getting rounded off!

You're welcome. I was lucky and managed to get 2 brand new ones. For the other car I picked the best of the used ones I had.

Oops. I didn't bother to look at my car. Parts manual shows them at the bottom.

Curtis wrote: Thu Sep 19, 2024 10:53 am Oops. I didn't bother to look at my car. Parts manual shows them at the bottom.

Ha! Well, we can definitely say they are somewhere in the backing plate!

Ya, and just try to buy a new one. I found it on evilbay sold out for $90.

Curtis wrote: Thu Sep 19, 2024 11:39 am Ya, and just try to buy a new one. I found it on evilbay sold out for $90.

Were those the two from an overseas seller listed as for a 411 Bluebird? I saw those a while back. The square adjuster looks a lot longer than the Roadster adjuster, probably doesn't matter?