How To Rebuild The Pedal Cluster On An Air-Cooled Porsche 911
If you are experiencing issues such as crunching into gear or inaccurate braking or throttle inputs, it may be time to rebuild your pedal cluster. While the procedure isn't difficult, it involves numerous small steps of which this guide outlines.
The air-cooled Porsche 911 has a set of three bottom-hinged pedals all connected to the vehicle controls through one simple assembly. Over time, the plastic bushings in this assembly tend to fail and cause excessive pedal play, resulting in reduced throttle, braking, and shifting control. This procedure shows you how to replace all the bushings and re-tighten your pedal performance.
Model Years This Job Applies To:
All manual transmission Porsche 911 models up to 1986.
Note: There are very slight differences in the pedal assemblies over the years, but their general construction and assembly procedure is similar. There is an automatic pedal cluster that will not be covered here due to its rarity. The 1987 and newer cars will also be excluded because they use a different gearbox and pedal cluster with a hydraulic clutch. We will be rebuilding a 1983 left-hand drive manual pedal cluster. Take as many photographs as possible of your disassembly to make sure you have a reference on how to put your particular pedals back together accurately.
Tools Needed To Complete This Repair:
- Floor jack
- Wheel chocks
- 4 Jack stands
- Drift punch set
- Bench vise
- Pliers Set
- Work gloves
- Safety glasses
- Penetrating oil
- 8-10 large diameter/fender washers (sourced at your local hardware store or big box store)
- 1 1/4" socket head cap screw and a nut with the same thread
- Pedal cluster bushing set (plastic or bronze)
- Clutch cable clevis (if the current one is damaged)
- Clutch clevis pin (if the current one is damaged)
- Clutch arm (if the current one is damaged)
- Clutch & brake pedal pads (if the current ones are damaged)
- Clutch return spring
- Brake return spring
- Brake pedal rubber bump stop
- New throttle bell crank cotter pin
*Your braking system will temporarily be disabled, so work on a level surface and secure the car so it can't roll away.*
Step 1: Raise Car on Jack Stands
Raise your car on four jack stands using this procedure. Always use a safe jacking procedure and add extra jacks or blocks to protect you as an added back up.
Step 2: Remove Floor Board and Throttle Pedal
Remove the driver side floor mat and the floorboard around the pedals. There's a single nut at the bottom of the floorboard holding it in.
Behind the plastic throttle pedal is a rod with a ball-socket. Pull the rod out of the pedal socket and remove the two bolts holding the pedal to the floor.
Step 3: Disconnect Brake Pedal Components
On cars from 1977 and later, behind the brake pedal you will find a long rod that travels from the base of the brake pedal up to a cavity along the back wall, directly above the pedals. The top of the rod is attached to the master cylinder linkage via a retaining clip and pin. Remove the retaining clip and pin and save these for the re-installation process. You can let the rod rest against the back wall and move up to the front trunk.
Locate the brake booster against the back wall on the driver's side of the front trunk. The large aluminum mount attached to the front of the brake booster can is fastened to the trunk floor by four nuts and one large bolt. Remove the one large bolt.
The pedal cluster is now completely disconnected from the brake master cylinder booster assembly. The brake pedal rod has a c-clip holding it to the base of the brake pedal. At this time, you can remove the c-clip and extract the rod.
The next part of this process is to remove the belly pan using step 2 of this procedure. On early cars with no power brakes (pre-1977) the master cylinder is connected directly to the brake pedal through the front bulkhead by a very short pushrod. Remove the two nuts holding the master cylinder to the bulkhead. The master cylinder will be held in place by the hard brake lines and the brake reservoir lines, but the pedal cluster base is now free from the master cylinder. Save the nuts and washers for re-use later. On cars from 1977 and later, simply remove the two nuts from the same location.
Step 4: Disconnect Clutch and Throttle Cables
The rod you just disconnected from the back of the throttle pedal connects to a small bell crank that pivots on the pedal cluster. The throttle cable is connected to that bell crank, and you should see the end of it poking out from behind the center tunnel. Remove the thin wire retainer and pop the throttle cable ball-socket off the bell crank.
The clutch pedal is connected to an arm on the opposite side of the assembly which connects to the clutch cable through a clevis and a pin. If you move the clutch pedal with your hand, you can see the arm moving the cable.
Depending on the condition of your clutch arm and clevis, the next step could take you one minute or one hour. There's a small bushing between the clutch arm and the clevis pin—if your car has been well maintained, you should be able to quickly pop the C-shaped retainer from the clevis and pull the pin out. If your car has not been well maintained, the clevis pin will have worn a groove in the bushing and arm which makes it extremely difficult to remove due to the limited clearance in that area. The pin may have a groove worn into it as well, and may not want to slide out. At this point, you're going to replace the clevis pin anyway, so do not be afraid to bend the clevis pin retainer to remove it. You may need to grab it with needle nose pliers and wiggle it along its worn-in slot to get it to slide out. In all cases, be patient and walk away to take a break if you are struggling with it (I know I had to take a couple).
By now, either your clevis pin popped off easily or you destroyed the clevis retainer getting the pin out. Regardless, your clutch cable should now be disconnected from the arm. Remove the two nuts holding the pedal cluster base to the floor immediately in front of the pedals.
Your pedal cluster is now free, and you can pull it out from under the dash and walk it to a safe place on the workbench.
Step 5: Disassemble Pedal Cluster
On the bench, inspect the overall condition of your pedal assembly. You may have some damaged paint on your pedals or base due to prior brake fluid leakage or exposure to water.
Inspect the condition of your clutch arm and the bushing. If your clevis pin came out very easily, the arm should be in good shape. If it gave you some trouble and you had to bend the clevis pin, you may see a groove worn into the clutch arm bushing or in extreme cases, a groove worn through the bushing and into the arm itself. You will be replacing the bushing in this DIY, but if the arm is damaged, you will need to replace the entire arm itself.
Most of the assembly is held together by a single roll pin located at the bottom of the clutch pedal. Mount the assembly in a bench vise, so the roll pin is accessible. Using a drift punch, tap the roll pin out of the clutch pedal.
Once the pin is out, remove the pedal cluster from the vise and pull the clutch pedal off. On 1977 and later pedal clusters the clutch return spring should fall out at this time.
You should now be able to slide the clutch arm out from the opposite side. In pre-1977 pedal clusters, the clutch spring on the right side will also slide out with the arm.
Remove the cotter pin and the throttle bell crank and extract the bushings. On 1977 and later clusters, remove the hex bolt on the left side and remove the brake pedal brace that attaches to the brake booster mount as well as the clutch pedal bump stop. At this point, nothing is holding the brake pedal in. You should be able to grab the pedal cluster base and pull the brake pedal and its return spring and bushings out by hand. Pull the rubber pads off the clutch and brake pedal, your cluster should now be completely disassembled.
It's highly recommended to arrange all the pieces into an exploded view and to take a photo like the one shown below. This single photo will help tremendously during re-assembly. Bag all of the small components, so you do not lose them.
Step 6: Reassemble Pedal Cluster
If your pedal cluster base, brake, or clutch pedals have any paint damage, this is a good time to sand and repaint them, or better yet, sandblast and powder coat them.
Your replacement bushings will either be plastic like the OE versions or upgraded bronze bushings that will last longer. We will be installing the bronze versions. The bronze bushings are impregnated with oil and do not need additional lubrication, but it is up to you if you want to oil or grease them.
Start with the brake pedal and insert the two large bushings and return spring.
Next, insert two bushings into each end of the shaft containing the brake pedal bump stop. Replace the rubber bumper if it's damaged.
Now inspect the clutch arm and check the end with the roll pin hole. This area has a tendency to crack. If it's damaged around the roll pin hole or at the clevis pin hole replace it.
Whether you buy a new clutch arm or reuse your existing one, it likely has a plastic bushing pressed into it. If you are replacing the bushings with bronze ones, your kit contains a tiny bronze bushing for the clutch arm. You will need to press out the plastic one and press in the bronze one.
You will need a bench vise and a spacer with a hole larger than the bushing's outer diameter. For this, you can use a short piece of pipe, metal tube, or a stack of washers taped together. You will also need a round metal rod that is smaller than the bushings outer diameter. In this case, you can use a 1/4" inch socket head cap screw with a nut screwed onto the end.
Carefully hold the clutch arm between the spacer and screw in the vise. Hold them such that when the vise presses on the bolt, it presses the clutch arm bushing out the opposite side into the hole of the spacer. As you compress the assembly with the vise, you will see the bushing slowly make its way out of the clutch arm then pop out completely.
Once the plastic bushing is out, grab the new bronze bushing and insert the tapered end into the clutch arm and squeeze with your fingers. It should stay partially engaged in the clutch arm.
Then squeeze the bronze bushing and clutch arm in the vise to carefully press it flush into the arm.
Insert the brake pedal with bushings and spring into the pedal cluster base. Then, insert the shaft with the brake pedal bump stop through both parts from the left side. Next, insert the two small bushings through the throttle bell crank tube in the pedal cluster base.
Insert the throttle cable bell crank and secure it with a new cotter pin. Install the brake pedal brace with the old lock-washer and socket head cap screw. Tighten this as much as you can by hand.
Grab the clutch arm (with its bronze bushing pressed in) and install the old cylindrical plastic spacer. Then, slide the clutch arm shaft through the right side of the pedal cluster base, through the center of the brake pedal and the shaft with the bump stop. The end with the roll pin should emerge out of the left side. At this point, you can slide the clutch pedal onto the end of the clutch arm shaft and line up the roll pin holes through both of the parts. The clutch arm should be pointing upward, and the whole assembly should be able to sit on its base. On early cars, you insert the clutch spring onto the clutch arm before sliding the clutch arm shaft through.
This next step can be difficult. You will need to drive the roll pin through both the clutch pedal and the clutch arm shaft with a hammer and a small drift punch. The part that makes it challenging is finding a way to hold the assembly down while you carefully tap in the pin. Use a nail or a small punch to keep the holes in both parts lined up as you drive in the pin from the opposite side.
You might be able to get away with a large vise or a large drop cloth folded several times on a table to protect the painted surfaces of the pedal cluster. Use masking tape to protect the paint from hammer strikes.
Use patience and slowly drive the pin through one side to the point of at least being flush with the opposite side. Now the clutch pedal, clutch arm, and all parts in between will be locked together.
Once the roll pin is installed, if any part of the roll pin is sticking out of the clutch pedal, rotate the clutch arm and make sure the exposed roll pin doesn’t crash into any part of the assembly.
On 1977 and later cars, the last major assembly step is installing the clutch pedal spring. You have to somehow hook the end of the spring over the grooved post on the clutch pedal and the grooved post on the pedal cluster base. Instead of using brute force, clamp the larger end of the spring into a vise and find a big stack of eight to ten large washers. Bend the free end of the spring back and forth to stick washers in between each coil to lengthen the spring.
Then walk the spring and washers over to the pedal cluster and hook the free end over the grooved pedal post. It should take minimal effort to pop the other end of the spring over the grooved post on the pedal cluster base.
Now you can pull out the individual washers with pliers, and the spring will retract to its normal position.
Pull the clutch pedal toward the rear of the car and the inner post should contact the rubber bump stop. If you let it go, the pedal should be retracted forward by the spring. Push the brake pedal forward, and when you let it go, it should be retracted rearward by the spring. Reinstall the heim-jointed end of the brake pedal rod into the post on the brake pedal and secure it with its old c-clip.
Step 7: Reinstall Pedal Cluster
Before installing the pedal cluster, clean up the floor under the pedals. There is usually a lot of debris caught in here. Touch up any floor paint damage to prevent rust.
Pedal cluster re-installation is the reverse of the disassembly from steps 2-4 above. Refer to the previous photos for reference.
Maneuver the pedal cluster back in the car and insert front studs through the front bulkhead. On early cars, you may need a helper to position the master cylinder rod between the master cylinder and the brake pedal as well as positioning the master cylinder through the front studs. Put on the nuts and washers just finger tight for now.
On late cars, maneuver the brake pedal brace and brake pedal rod through the cavity to the master cylinder linkage and insert the front studs through the front bulkhead. Seat the pedal cluster base on the floor over the two floor studs. Install four washers and nuts over the four studs finger tight.
Reconnect the top of the brake pedal rod to the master cylinder linkage with the pin and secure with the retaining clip.
Reconnect the brake pedal brace to the aluminum mount at the front of the brake booster. Torque the bolt to 46 N-m (35 ft-lbs).
Insert the clevis pin through the clutch cable clevis and clutch arm and snap the clevis pin onto the clevis.
Snap the ball socket of the throttle cable over the ball of the throttle bellcrank and reinstall the retaining wire.
Push the pedal cluster base forward against the front bulkhead. From under the car tighten the nuts on the 2 front studs. On early cars torque the master cylinder mounting nuts to 25 N-m (19 ft-lbs). Inside the cabin tighten the nuts on the two floor studs by hand.
On all cars, reinstall the belly pan per step 7 of this procedure.
Snap the ball end of the accelerator rod to the socket on the back of the plastic throttle pedal and install onto the floor. Tighten the two bolts by hand.
Actuate all three pedals by hand and make sure none of them stick or bind anywhere on their travel. They should feel slightly smoother due to the new bushings. Reinstall the floorboard and secure with the single nut tightened by hand.
Step 8: Test Drive
Put the car back on the ground. After completing a few stops in your driveway, take the car for a short, low-speed test drive to test pedal function. Your pedal cluster is now ready to give you years of smooth heel-and-toe spirited driving.
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Written By: Jose Martinez
Having explored the fields of aerospace, power generation, automotive aftermarket, and concept car engineering, I'm now a development engineer for Mazda North America. In my spare time, you can find me wrenching on anything, but mainly cars of the air-cooled variety. @joe_engineer