Stock brake refresh

[Michael]

Despite surfeit of information on upgrade options (in this sub-forum, or the FAQ), and some wise advice on leaving things alone for the more modest applications, there seems to be little information regarding refreshing of stock brakes.

 

Here’s the problem: car has been in hibernation for years, maybe decades.  Fluids are old.  Pads are probably from the early 1990s. Brake lines were custom bent and installed around the year 2000 (long story), but the brake hardware (calipers, rotors, drums, cylinders,…) were left alone.  Car was driven sporadically over the years,  but hasn’t been a daily driver since 1999.

 

Thus, the question: what ought to be refreshed, repacked, replumbed?  Having sat for a while, the rear drums seized.  A winch eventually un-froze them. The brake pedal is somewhat (not entirely) mushy, and hitting the brakes “hard” results in a jerking to the left followed by a four-wheel slide (tires are probably 30 years old).

 

Do we have a step by step checklist, for what ought to be done?  And to reiterate, this isn’t a plea for advice on upgrades.  I just want this car to brake and handle like it would have done, 25+ years ago.

[Mayolives]

Recently I was in a simular situation with my 78 280z.  It had been resting for many years.  I had to beat the rear drums off.  All the rear hadrware was rusted and in bad shape.  After measuring the inside diameter of the drums, I found both to be larger than spec.  They must have been turned in the past.  The front system was rusted, had bearing grease and brake fluid where it shouldn't be.  The brake and clutch master cylinders were filled with dark gunk and the master vac was really rusted and probably leaking vaccume.   I decided  not try to save any of it and replaced all these parts with the best I could locate.  I had to go with iron drums beacuse AL ones are no longer available.  After removing the old parts, including the clutch slave, I connected a pressure bleeder to the supply lines where they connected to the master cylinders and pushed a little fresh fluid thrugh them to get rid of all the old fluid.  I probably could have saved some of the old parts and spent the time to rebuild them and clean up the hardware, but I knew from experience, starting off with fresh parts was the better way for ME to go.  It's all pretty straight forward work.  Replacing the rear shoes was a little challenging because the two bigs springs gave be a hard time.  I finally used a large clamp to hold the shoe on one side in place against the backing plate and then pushed the other side back in place.  I have brake spring pliars but just couldn't find a way to use them on this set up.  Also I have a brake tool with a handle on one end and little cup on the other end that really helps to remove and re-install the two shoe holders on each side.  Be sure to check your e-brake cable to see if it's free before you start.  If not it will need to be lubricated to free it up or replaced.  Also, there is a threaded adjuster for the e-brake on the bottom of the rear brake hardware.  It spreads that shoes out towards the drum surface.  I will need to be installed with it made to be in it's shortest position.  You can adjust it out manually when you are done to make it longer, a little at a time until the brake drum drags a bit when you slide it back over the sheos.  The final adjustment can be make by pulling the e-brake handle a few times until it tightens up.  I installed new soft brake lines on all corners but saw no reason to replace the hard lines.  Be sure to install the rear shoes properly.  The lining on one side is longer than the other.  (Front facing shoe vs rear facing shoe)  I forget which is which but can get back to you if needed.   Also, I removed, cleaned and repainted the backing plates and the front wheel hubs then replaced the front wheel bearings and seals before I reinstalled them.  Could I have repacked and saved to front bearings?  Perhaps.  But now I feel better about the whole job and It didn't cost a fortune.  Take some pictures first if your not certain about anything.  The factory service manual has good drawings that will guide you if you need to help.  It's not brain surgery.  Just nuts and bolts.        I 

[Mayolives]

Also, I didn't address the front brakes in my post above.  After removing old system and cleaning/ painting what was needed, I installed new rotors, calipers and pads.  Touqued them to spec.  Be sure to use brake lube on the long pad pins.  Pad instruction usually will show you where to apply lube.  There is no brake adjustment for the pads.  They will take care of themselves.  Be sure to bleed all the air out of the entire systems you had apart.  Can be accomplished with a power bleeder or a friend with strong legs.  Don't over tighten the large nut on the spindle when you replace the hub.  Do it just enough for it to spin freely but not have  the hub lose on the spindle.  

[Michael]

To summarize, the approach appears to be:

 

1. Disconnect lines to the calipers (front) and slave cylinders (rear).  Pass fluid through the whole system.  Hopefully the master cylinder and vacuum booster are OK.  If not, do something...

 

2. Replace the slave cylinders (rear) while being mindful of the parking-brake pawl.  Check drum diameter, and if out of spec, replace.  Replace shoes.

 

3. Replace the calipers (front), rotors and pads.  Presumably also do the bearings... or split the hubs/rotors and just replace the rotors?

 

4. New fluid, and bleeding.

 

5. Careful adjustments in the rear, while the front is self-adjusting.

 

I found one source for parts, here: https://zcardepot.com/collections/280z?constraint=rear-brakes .  Any other recommendations?

[grannyknot]

Personally I would start with both the brake and clutch master cylinders and work downward from there. Pull them out, dismantle and clean them. I can almost guarantee they will be full of muck, check the cylinder walls for corrosion and pitting, if they are smooth you may be able to just reassemble and put them back in to use but at least you will know they are in good working order.

Here is the last M/C I removed and the proportioning valve.

 

 

[Miles]

"Do we have a step by step checklist, for what ought to be done?  And to reiterate, this isn’t a plea for advice on upgrades.  I just want this car to brake and handle like it would have done, 25+ years ago."

 

These cars are pushing 50 years old.  In the interest of your safety and public safety rebuild the brake system.

 

Here is the list of parts to replace.

• Booster
• Booster vacuum hose and check valve
• Master cylinder. Lear how to bench bleed it. Learn how to adjust the booster push rod length. Too long and the brakes will lock up.  Too short and the pedal travel will be excessive.
• All rubber brake lines replaced with SS flex lines.
• Front: calipers, pads, rotors and wheel bearings
• Rear: drums, wheel cylinders, shoes, springs, retainers. Learn how to adjust the brakes.

Pads and shoes:  Carbotech  AX6  https://ctbrakes.com/brake-compounds2.asp

Carbotech AX6 pads have excellent cold bite which is what you want for a daily driver. Call Carbotech to get a quote for pads and shoes. You may have to send them the old shoes as cores.

[Miles]

Useful information:

• Download a Factory Service Manual (FSM). http://www.xenonzcar.com/s30.html

• Download electrical schematics for your car. PDFs are easier to read than those found in books. Some are in color.

• Buy the book How to Restore Your Datsun Z Car by Wick Humble. It will save you hours of searching for "how to" info.

• Focus on searching Hybridz as 99% of questions have already been addressed.

• Start bookmarking Z car parts suppliers. Remember these are 40 year old cars and will need restoration to be safe and drivable.

• Join ClassicZCars.com website and search there as well.

• Become well informed about modifications before asking questions. People will be more inclined to answer informed questions

https://www.datsun-240z-upgrades.net/ Recommend the headlight relay harness

http://zhome.com/

https://www.zcar.com/

https://www.classiczcars.com/

http://www.zcarparts.com/

http://www.arizonazcar.com/

http://www.xenonzcar.com/reference.html

[Michael]

Good points, Miles, but with all due respect, this is not a "newbie" question.  I've owned and worked-on this car for 22 years.  Wick's book (among others) has probably been sitting on my shelf for nearly 30 years.   It's just that the car (not unlike the book) has sat more or less ignored for the majority of those years.  Recently I moved, together with the car, to a locale where I have no garage, no parking space, no tools, no place to work on the car, and no time to work on it either.  But the car was too precious, too storied and too unique to sell.  And paradoxically, even Quixotically, I have no what that of which I had nearly zero, for so long: motivation.

 

The point now is to start and maintain a discussion on modest, incremental steps to take a car from being a piece of furniture, to a piece of transportation.

[grannyknot]

21 hours ago, Michael said:

The point now is to start and maintain a discussion on modest, incremental steps to take a car from being a piece of furniture, to a piece of transportation.

Well you're right to start with the braking system then, go through each area of it if just for peace of mind.