1971 Body/Chassis FSM

1971-74 F Engine FSM

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Rebuilding Your Front/Rear Drum Brake Wheel Cylinders


Disclaimer: Any ideas you get from this site should be checked against a qualified mechanics opinion. Brake work should NOT be taken lightly! If you have ANY doubts as to your ability to do a quality job, stop right now, and pay someone to do it right! I recommend you not do this rebuild, but just get all new parts, take them to a certified mechanic, and have him install them.

Overall Brake Notes

On older Land Cruiser like mine there are 4 different styles of wheel cylinders on one truck! Front and rear and left and right. They are NOT interchangeable, though they WILL fit! First of all the four front cylinders are SINGLE PISTON while the four rear ones are DUAL PISTON. The wheel cylinders are also 'handed', meaning they are for a certain side. Fortunately for us dumb mechanics Toyota was smart enough to cast into the cylinder body a big L or R to keep you from getting confused. ( That did not stop the PO of my truck! He had the front cylinders swapped resulting in the truck NEVER having good brakes.)

Front Brakes

If your wheel cylinders are in pretty good shape it makes no sense to buy new ones when the cylinder cups wear out. The wheel cylinders on the FJ40 are super simple to rebuild.

Get a cup rebuild kit from NAPA, SOR, or you favorite auto parts store and follow along as we rebuild them. I got my front cup kit from Advanced Auto Parts. They were made by Beck Arnely and are Advanced Auto Part # 18020538 (Beck Arnely Part #071-4758. Rear cup kit is Part #071-4816). This is a minor kit and does not contain the spring and spring seat. Only the cup, dust boot and bleeder cap.

I am going to assume that you have removed the cylinders, taken them apart and cleaned them up. See the Knuckle Rebuild section for how to remove all the brake components. The following tools are needed for rebuilding the cylinders.

Tools Needed

10mm Flare Nut Wrench
For removing the bleeder screws if you didn't already.
Brake Cylinder Hone
Any auto parts store will have this.
Brake Fluid
To wet the hone
Calipers or Micrometer
To measure the diameter of the cylinder bore and piston. If they are worn past the limit the cylinder piston will hang in the bore.
Brass wire wheel
To remove the build up from the cylinder piston. Steel wheels will remove material! You can also use a scotch pad. (Green kitchen scrubby)
To clean the parts


Manual page

Fig. 1

Page from manual

Exploded View


Actual Cylinder


Fig.1 shows an exploded view of what is inside the cylinder from the factory manual. Fig. 1A shows a picture of my wheel cylinder. From left to right: Wheel Cylinder Boot, Cylinder Piston, Cylinder Cup. Spring Seat, Compression Spring, Cylinder Body, Wheel Cylinder Adjuster mechanism. Note: DO NOT mix the adjusters up! Some are left handed threads, some are right! I will explain below what goes where. Work with one wheel cylinder at a time to avoid mixing up parts. If you do mix stuff up I'll explain what goes where later.

Scored Cylinder Wall


Ready to Hone

Honing Tool

Fig. 3



Cylinder Honing, Polishing and Cylinder Piston cleaning

  1. Choose a cylinder body and matching piston to work with. Clamp the cylinder piston carefully in the vice and using the brass wire wheel, GENTLY remove the buildup on the piston. Set the piston aside.
  2. Clamp the cylinder body in the vise, piston bore up, as shown in Fig 2. Get some clean brake fluid and coat the inside of the piston bore with it. Mount your hone (See Fig. 3.) in a variable speed drill then dip the stones in some clean brake fluid. Now compress the hone into the cylinder bore . If your hone has adjustable tension set it according to the manufactures recommendation or so there is firm tension holding the stones against the cylinder wall . See Fig. 4
  3. Using a variable speed drill at low speed with plenty of brake fluid as a lubricant, run the hone the full length of the bore in an up and down motion. You are trying to make a cross hatch pattern. Run the hone long enough to smooth out the bore, but do not over hone! I found that with a severely corroded cylinder that about 300 strokes up and down got the most of it. Do 100 strokes then wipe out the cylinder and clean off the stones. The stones will foul if you don't clean them, cutting their effectiveness.


Honing the Cylinder

Fig. 4

Honing the Cylinder

Polishing  the bore

Fig. 5

Dremel Polishing

Polished Bore

Fig. 6

Polished Bore

  1. Check that you have removed all pits and corrosion. Repeat the honing till the bore is smooth and free of all defects.
  2. Wash out the bore with soap and water to remove all traces of the hone grit.
  3. Next you need to polish the bore to as fine a finish as possible. There are several ways to accomplish this. I used two things: One I cut a piece of 1000 grit (very fine) sandpaper to fit the bore of the wheel cylinder. Then inserted the hone so that it was pressing the sandpaper against the inside of the wheel cylinder. I ran it up and down 50 times, wiped it out then used my Dremel Tool with a polishing felt and rubbing compound. See Fig. 5. I followed this with a metal polish. If you don't have a Dremel tool then get a 3/8" wooden dowel rod and cut a 5" piece off. Next make a slit in the end with a knife and insert a folded piece of very fine grit sandpaper into the slit. Chuck the dowel into your drill and use this to fine sand the bore. Next put a piece of old rag soaked in a metal polish in the slit and repeat. You want that bore to SHINE! The purpose is to help the cylinder cup make a good seal against the bore. A smooth bore means a tight seal with less chance of leakage. A smooth bore will also slow wear of the cup. See Fig. 6 for a finished bore.
  4. You may also want to hone the adjuster side of the cylinder to remove any corrosion. It does not need to be polished unless you are just really bored.

Measuring Clearances

I know you just put a lot of work into prepping that cylinder but if the piston clearances are now too large due to your honing and polishing and you put it in service you will experience leakage past the cups. We now need to determine if this cylinder/piston combo will work.

  1. Start by measuring the inside diameter of the just honed Wheel Cylinder bore. Write this down. Now measure the outside diameter of the cylinder piston. Subtract the piston diameter from the bore diameter. There should be no more than six thousandths (.006) difference between the two. Measure in several locations then average to ensure a good reading. If the readings are more than the allowable difference then you should either look for new replacements or have all your friends send you their old wheel cylinders! (They all converted to disk brakes long ago of course) Mix and match pistons and cylinders until you have a good set. The tighter the better but don't match a set so tight the pistons bind! I would allow at least .002 for thermal expansion.

Assembling the Cylinder

  1. Use an 8mm x 1.25 tap to clean out the four mounting bolt holes. Then use a 10mm x 1.25 tap to clean out the bleeder screw threads. Last use a 12mm x 1.25 tap to clean out the banjo bolt threads. See Fig. 7.
  2. Clean the cylinder body and piston of all dirty brake fluid with soap and hot water. Use compressed air to blow out all the water and wipe it down with alcohol. Get your rebuild kit out.
  3. Place all the parts except the dust boot into a small container of clean brake fluid.
  4. Place the wheel cylinder upright with the piston bore up. See Fig. 8.
  5. Coat the inside of the cylinder bore with clean brake fluid.
  6. Place the Spring into the center of the bore and put the spring cap on top of it with the large end up. The spring will fit in the recess on the back of the spring cap. See Fig. 9.
  7. Place the rubber cup on top of the cap with the large recessed end facing into the cylinder ( flat face facing out). See Fig. 10.
  8. Install the rubber dust boot on the metal piston. Use the piston to push the rubber cup in to the cylinder. While holding the piston in, use a small screwdriver to seat the dust boot around the lip of the cylinder. Make SURE it's seated all the way around. Twist it back and forth a couple of times to seat it.
  9. Coat the adjusting screw bore with grease or anti-seize compound, coat it good! Remove the adjusting screw (to prevent air lock) and place the adjuster piston into the bore and rotate it back and forth several times to coat the piston. Remove and ensure it's coated well. Put the adjuster screw back in.
  10. Attach the adjuster lock spring after coating the screw with some anti-seize.
  11. Your done! Wow! One down and three or seven to go! See Fig. 11.

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