Hi Every one,
just installed a pair of rear outer wheel bearings . The next step of this
winters 928 "things to do" is rear crank seal, pilot bearing, & clutch pac.
I have factory micro fiche for a guide. I have a few start up questions, should
the torque tube & trans "shoved back" toward the rear of car, do you have to
take the bell housing of to remove fly wheel, and dose the fly & inter-plate
warp? if so what are the spec's wear , how much can be cut, ect if is such
the trans and torque tube stay where they are ! You must drop the exhaust ,
remove starter( disconnect the battery )or leave it hanging on the lower bell
housing and remove the slave cylinder (leave hose attached ). The lower bell
housing cover (6 bolts ) drops down and everything is right there . Read the
manual and be sure to shim the pressure plate BEFORE unbolting the pressure
plate . When you pull back the clutch short shaft do it only about
1/2 to 3/4 inch . Read the manual ............ with the car on a lift the clutch R and R is maybe 2 hrs AFTER you have done one . There are other steps required ........
Master Clutch Cyl, replacement:
I have a 85, 928s, American edition, 5 speed.
One will note very quickly that getting to this part, is about a nightmare as it gets if you have big hands. However, it was not all that bad overall. The hardest part of this job is to remove the power brake assist unit, but once that is done, it goes easily.
Remove the brake lines from the brake master cyl, put duct tape over the ends of the tubes to keep them clean, move out of the way a little bit. Catch any fluid with a cloth. Clean off any brake fluid on the opening area of the master cyl from the lines, and cover them with duct take to keep clean. I used a 8 oz coffee cup for this, remove the blue line and catching the brake fluid with the cup. Plug the blue line. Remove the master cyl and reservoir as one unit.
Inside the car, remove the clip from the brake push rod. Measure the distance from the front of the seat to the extended travel of the brake pedal and place a piece of wood to keep the pedal down. The farther you get it down, the better. Using a pair of vice grips, put duct tape on jaws as to not mar the plunging rod on the power assist unit and place the grips to hold the rod as to not let it go back into the unit.
I have found out the hard way, that getting that sucker out of there, is not easily as one may think. As far as I could get the brake pedal down to move that plunger rod forward, was still not enough to get it out of there. I tried too, but after an hour that was it. Next:
Remove the air intake box, remove the air pendulum, vacuum hose to the booster., spark plug wires. Remove the valve cover. Inspect the seals for the spark plug valleys, as I had 2 that were just starting to weep and several of the bolt "O" ring seals holding the cover. I also did a cam tower seal too while I had the cover off. Clean up any debris that may fall into the open head, clean up the surrounding areas where the valve cover gasket sits. Cover the open head area with a clean cloth as to not let anything get in there. Remove gasket from valve cover, clean, set new gasket and spark plug seals in using appropriate type material. I used just a little of the blue silicone to hold it in place.
Check the seals on the brake master reservoir, replace if there leaking at all. Remove the nuts for the brake assist unit. It will basically fall out now with the extra space from removal of the valve cover. Now is a good time to really inspect the back of the master cyl for any leakage and look inside the power assist unit for any signs of brake fluid. If there is any, now is the time to replace the master cyl.
Look down and you will see the clutch master cyl. Remove the clutch line, leaving the blue line in place. Use a rag to catch any brake fluid that comes out of it, I did not have but a few drops. Place a piece of duct take over the open line to keep it clean and to not loose any fluid.
Go inside the car, remove the holding clip for the clutch master push rod, pull the rod out. I used my old rod, but you can use the new one supplied with the master cyl, just adjust it to the correct length as your old one. Check the plastic bushings of both, brake and clutch rods to arms, lube. Pull back the insulation that is there and pull the rubber bellows from the clutch master off. Mine was weeping. Remove the 2 bolts that hold the cyl in place, leaving them in place. Clean up the area if necessary of any brake fluid. Go back out and pull the cyl out. Mine just fell out.
Clean up the surrounding area of any brake fluid. Once everything is cleaned putting everything back together is easy.
Attach blue line to clutch cyl then have someone hold it in place so you can bolt it back up from inside the car. Remove the duct tape from the clutch line and put it in half way only. Using a short stubby line wrench works great for this.
Attach brake power assist unit. Attach rod for brake to pedal, remove wood from inside car, then remove vice grips holding the power assist plunger . Attach the brake master cyl & reservoir as one unit. Before attaching the blue line, make sure that it is gently sloping down to the master clutch cyl and that there is no area where air can sit in it. I used a new one and I had to cut 4" from it . Attach blue line, remove all duct tape, attach brake lines, but do not tighten them (place a rag around each fitting to catch any fluid while fluid drains from them, the fluid will replace the air in the top of the lines) ..... fill reservoir with brake fluid. I did not have a bleeder so I had to do it by hand. Look down at the line at the master clutch cyl, you should see a few drops of fluid coming out of it. If not, loosen the fitting u ntil you do. The cyl is filling up with fluid now. The little bit of air that was in the flange area in the clutch cyl is now semi filled with fluid and air. Tighten up that fitting when it is dripping pretty good. That little bit of air is now in the top of the cyl. Check the fluid level in the reservoir. Go back in the car and with a pair of angled circlip pliers, remove the circlip, while using the clutch rod to push in the plunger. What your doing here is burping the clutch master cyl. There is really not much of a way around this. Once the clip is removed and the washer that is behind it, move the plunger up and down just a little bit, until you start to see brake fluid with air come out. Catch any fluid with a rag. Continue this for a minute to make sure all air is removed. Pressing in on the plunger, replace the washer and circlip. Attach rod to pedal and lube.
Check brake fluid, fill as necessary. Have someone inside the car to assist. Lightly tighten the brake lines only. Depress brake pedal, loosen up one brake line until the little bit of air that is there is removed, tighten up line, release brake pedal, repeat for other line. There should be almost no air in there and what is, will be forced out. Keeping the brake lines capped with duct tape and clean helps with this, plus gravity will help to feed the brake fluid down to fill up the little space in the flange where air was. Once the lines are bled, do the same for the brake master cyl. There was only a few little bubbles of air in mine only. You do not want air to get into the lines, otherwise you will have to bleed out the all the calipers... more needless work.
Attach the valve cover and the other items that were removed. Attach brake vacuum hose. Start car. Check brakes, clutch. All should be 100%. This is basically a 2 hr job, without doing the work on the cam tower as I did. Maybe 3 hours if you have a cold six pack on hand.