From: antelman@sd.cts.com (Douglas Antelman) Date: Sun, 7 Jan 96 21:32 PST Subject:Disc Brake Service I was feeling ambitious, so while I had the Z in the air, I also serviced the front brakes. While the braking performance was OK, the pads were worn and one of the rotors was below the minimum regrind thickness of 10.5 mm. (The other rotor was replaced about 2 years ago). The calipers remove easily, simply remove the brake pipe (remember to use your 10 mm flare end wrench) and 2 17mm hex head bolts hold the caliper in place. They usually slide off, but sometimes a few blows with a hammer will help them off. Catch the brake fluid in a drip pan. Note: It is possible to service the front brakes without loosening the brake pipe BUT I feel it is much easier to compress the caliper pistons if the pipe is off and any good brake service should involve bleeding out old fluid anyway. Take the caliper out to the drive and rinse off the brake dust. Chances are by now you're not replacing asbestos pads, but if you're unsure, get some brake-cleen spray. Whatever you do, don't inhale brake dust! The retaining pins are held by 2 spring clips. Remove the clips with a needle-nose pliars. If the pins are rusty, drive them out with a punch. Clean the stainless steel backing plates. If you're calipers are all corroded (the body is aluminum, so the won't rust) you can have them bead blasted or if you use silicone brake fluid, you can spray them with aluminum paint, which gives close to an original appearance. If you use regular brake fluid, paint is not an option, as the fluid will eat right through it. Once the pads are out, you can compress the caliper pistons. I used a 4" C-clamp for this and it works quite well. Do this over a tray, as the fluid will come out as the pistons are pushed back into their sleeves. The pistons should move freely- if they do not, the caliper will need to be rebuilt, or turned in as a core for an exchange unit. My calipers all were OK- part of the benefit of silicone brake fluid- your calipers and wheel cylinders will last a very long time. In fact, I have never had any brake problems (other than worn drums, rotors, pads, shoes) for the last 14 years on this 240-Z. I used the "blue" gunk anti-squeal compound between the stainless steel plates and the pads. My Z uses semi-metallic pads, and they tend to squeak when cold, so we'll see if this stuff helps them. On the side that needed the new rotor, I unbolted the hub from the inside of the rotor, and the hub can be hammered out of the rotor. Part of any disc brake service should be cleaning old grease out of the hubs and wheel bearings and re-packing them. Just make sure your hands are clean before handling the rotor- and keep some alcohol on hand in case you accidentally get grease on the rotor. I remounted the rotor/hub unit and tightened the outer wheel bearing to spec. Clean the rotors off and your hands, before mounting the caliper-pads unit. Refit the brake pipe and the 2 bolts that hold the caliper assembly on. Now it is time to bleed the brakes. I generally use an assistant for this step. I use a special brake bleeding jar, which is especially suited to the task. Take an old jelly or pickel relish jar and poke 2 holes in the lid with a screwdriver. Insert your bleed hose into the hole. The snug fit will keep the hose at the bottom of the jar, below the fluid level. No more air getting sucked in during the bleed operation and no more accidental spills on your garage floor. When you're not using the bleed jar, insert the free end of the hose into the other hole. I start with 1/2" of fluid in the jar and have my assistant pump the pedal slowly until all the old, dirty fluid and air bubbles are expelled from the caliper. When bleeding the front brakes, bleed the RH side first, then the LH side. Oh- and if you try and try and you can't get the air out- you've got the calipers (L and R) mixed up! The bleed screw MUST be on top- it happens! Once happened to me when I got a pair of rebuilts and they were both the RH side! On the last downstroke of the brake pedal, I have my assistant hold the pedal down and then I tighten the bleed screw. During the procedure, I have my assistant check and top up the resevoir as needed. In some cases, you may want to bleed the master cylinder and rear braking system as well, particularly if either resevoir has run dry. That's it! I checked all connections, remounted the road wheels and off for a test drive! In a few hundred miles, I'll unblot the wheels and check the condition of rotors and pads to be sure that they are propely bedding in. Doug Douglas Antelman Encinitas, CA '71 240Z '69 2000 Roadster ------------------------------ From: antelman@sd.cts.com (Douglas Antelman) Date: Sun, 7 Jan 96 21:32 PST Subject: front end work part I Part I: Tie road ends and rack and pinion I Took my '71 Z off the road this weekend for some front end work. If you have interest in tie-rod end replacement, rack and pinion bellows replacement, disc brake service, etc. read on. If you have an early Z car that "wanders" on the road, you should first check the following areas: rack bushings, wheel bearings, tie rod ends and ball joints. Most people fit oversize rack bushings, which perform better than the original part the car came with. If you have a 240-Z and they have never been replaced, it will be quite obvious- the steering will be vague and float. The front wheel bearings, if kept properly lubed and with the correct pre-load, will last a very long time. If they are too loose it will be evident, when the car is jacked up and one can wobble the wheel on the hub. The next place to check is the tie road ends. In my case the RH tie rod end needed replacing, for the rubber boot had split, allowing the joint to dry out. Note: if you have a damaged boot, you can drive on it for a while (in California for even longer) provided you keep injecting grease into the joint. The boot is not available as a separate part, so if it is destroyed, you will have no choice but to replace the entire part. Try to choose a good quality tie-rod end, with an integral grease fitting. If no grease fitting is present, you can drill a hole in the underside of the joint and thread with a tap and install your own. But its worth the extra few $ to get a good part that already has the fitting. When replacing tie rod ends, it is best to replace in pairs. Do one side at a time. Note the # of threads visible on the arm that threads into the tie rod, as you'll want to get a reasonable approximation of toe in before you take it in to be aligned. The tie rod connection to the R&P can be loosened by using 2 opposing wrenches- try some liquid wrench first, as these threads tend to be stiff or rusted. The tie rod is secured with a single hex nut into the steering knuckle, either a self-locking type or the type that uses a cotter pin. It may take a "ball joint fork" to separate the tie rod end from the collar. In some extreme cases the steering knucle will have to be heated with a torch to expand it. While you have the tie road off, check the condition of the rubber bellows, or boot. If there are any cracks or splits, now is the best time to replace them. The boots pull over the end arm of the R & P unit. In some cases the steering :float" is not due to the tie rod ends, but the inner tie roads, or ball end units in the rack and pinion. These are normally covered by the boot and generally last longer than the external tie rod ends. They do wear though, and in very high mileage situations they develop play. If there is any slop in the inner joint, it must be tightened (these joints have adjustable load) or replaced. According to the shop manual, if the end arm falls under its own weight, then the joint is too loose. While you're under the car, take the time to refill the grease resevoir on your R&P unit. Preventative maintenance plays big time in your rack and pinion's lifespan. Ask someone how much a replacement R&P unit costs and it will be enough to get you out in the garage this coming weekend. Inject grease into the ball joints and tie rod ends as well. I will not cover ball joint replacement right now, as I replaced these about 3 years ago. Douglas Antelman Encinitas, CA '71 240Z '69 2000 Roadster ***********CHECK IT OUT- my WWW PAGE!********************* 240-Z and Roadster pictures and text with links to other neat places..... http://users.aol.com/antelman/index.html **********************************************************