This is a set of instructions to reseal Honda 4 cylinder engine distributors, not all Honda distributors can be resealed. Check online to see if your particular distributor model can be resealed before you attempt this procedure. Honda distributors have a shaft seal inside the that tends to leak, when this seal leaks you will find oil in the lower part of the distributor cap (photo 1).
The reseal procedure is medium difficult and it takes up to an hour to complete, this instructable is aimed at beginner to medium skilled owners that have done basic maintenance such as oil change, tune up including spark plug replacement, distributor cap and rotor replacement, battery replacement.
There are only two replacement parts needed, one is the outer distributor o ring (this is a simple rubber ring) the other is the distributor shaft seal, which looks exactly like a camshaft or crankshaft seal except it is very small (photo 2).
There are several tools needed to carry out this procedure but none of them are specialty tools so if you have a basic set of tools that include metric sockets, socket wrench and screwdrivers you can accomplish this task.
Tools needed (photo 3)
Phillips and flat head screwdriver
12 mm combination wrench
1/4" ratchet wrench
1/4" drive 8 millimeter socket
14 mm socket or equivalent diameter round tool
Supplies needed (photo 4)
Oil based sharpie paint pen or white out
Alcohol-based solvent, such as brake clean
Penetrating oil such as WD-40
If you suspect the distributor seal to be leaking start by looking at the valve cover gasket below the oil cap at the corners, see figure one. There should only be dry silicone sealant (photo 5), if there is oil at this part of the cylinder head, it means that the valve cover gasket is leaking, that repair is not covered in this instructable.
If you find oil at the lower portion of the distributor cap (photo 6), there is a good chance the distributor inner shaft seal is leaking and you will learn how to fix it following this instructable.
Step 1: Before Distributor Removal.
Disconnect the main distributor harness connector, there may be one, two or even three connectors to undo depending on year and model. Use a Flathead screwdriver to press on the locking tab that secures the connectors to harness brackets.
In most models there is a metal clip securing the harness to the distributor housing, use a flathead screwdriver to open the clip and detach harness from housing.
Use a 1/4'' drive socket wrench and an 8 mm deep socket to remove the three bolts attaching distributor cap to distributor.
Remove distributor cap with spark plug wires still attached and set aside, by leaving wires attached to distributor cap you will prevent mixing the wires at the time or reassembly which could cause engine not to start up.
Also pay attention to the small metal spring inside ignition coil, this spring is only pressed in and may fall when distributor cap is being removed (photo 5).
Mark distributor housing and cylinder head, this will ensure that the timing is the same after reseal.
Step 2: Double Check Distributor Shaft Seal Leak.
Once distributor cap has been removed you can double check to make sure the oil leak is actually coming from inside the distributor.
Use a flashlight to look inside at the most inner part of the shaft where the shaft seal is located, if there is a trail of oil under the seal then you have confirmed the oil leak (photo 2).
If the inner shaft seal area is dry of oil as well as the valve cover corners inspected in step one but the distributor cap is wet, the outer distributor o ring may be the only leak and the distributor will still need to be removed to replace the ring.
Step 3: Remove Distributor From the Cylinder Head.
Use a 12 mm wrench to remove the three bolts that hold the distributor to the cylinder head.
The distributor will come off now if you wiggle the unit with both hands. If it feels like the distributor is stuck on, you may use a flathead screwdriver to pry it loose (photo 4) but do not use excessive force.
Step 4: Replace Distributor Outer O Ring.
If there is no oil on the inside of the distributor or cap as described on step 3 but the outer o ring still needs replacement, follow this step.
Use a metal pick or small flathead screwdriver to pry under rubber o ring and remove it, if the seal is very old it will have turned into hard rubber and crack when screwdriver is used to pry on it.
Install outer o ring using your fingers to roll seal into the grove.
Step 5: Disassemble Distributor (part 1).
The use of a vise to hold distributor is recommended but not necessary.
Remove distributor rotor by loosening phillips screw attaching it to the distributor shaft. If rotor does not slide out easily, use a screwdriver to carefully pry it loose, you may need to spray penetrating oil such as wd-40 to loosen up rotor.
Remove plastic cover around ignition coil and ignition module, do not discard.
Remove ignition coil leads by loosening two screws, the ignition coil case is labeled with a positive + and negative - sign and the length of the wires will only allow them to go on at the correct location, it is still a good idea to use paint or white out to make your own marks (photo 4).
Remove cylinder pick up coil by loosening two attaching screws, and set aside (photo 5 and 6).
Connected to ignition coil are 4 wires with rubber protectors on terminals, you only have to disconnect one of them to be able to remove ignition coil from distributor housing. (photo 7 and 8).
Remove ignition module by loosening two attaching screws, and set aside (photo 9).
Step 6: Disassemble Distributor (part 2).
Remove distributor shaft bearing case by loosening the three attaching bolts.
Remove distributor coupling. It is important to mark coupling and shaft to ensure it goes back on the same way at reassembly. Use metal pick to remove retainer and slide pin out (photo 2-4).
Pay attention to thrust washer in between coupling and distributor case, be careful not to misplace it.
Remove bearing case and shaft as one piece, it should slide out by slightly pressing on it by hand. If it feels stuck, you may use the screwdriver handle to gently tap the end of the shaft.
Step 7: Remove Distributor Shaft Seal.
Remove oil seal using metal pick, insert pick under seal and pull up to remove it, oil seal is lightly pressed in, it should come off with light pulling pressure.
Step 8: Install Distributor Shaft Seal.
Oil seal is pressed by applying light pressure but in some cases a small hammer may be used to drive seal.
Use both index fingers to reach in and drive seal in (photo 2).
If driving seal by hand is too difficult you may use a 14 mm socket to drive seal flush with distributor case (photo 5).
A different size socket may be used, depending on tool set, as long as it is of the same diameter size as the seal.
Step 9: Reassemble Distributor.
Use fine emery cloth to smooth out distributor shaft surface where the oil seal will ride (photo 1).
Install shaft assembly by sliding shaft though oil seal onto the distributor case. Ensure that bearing case is flush with distributor case (photo 5), then install three screws.
Install coupling to end of distributor shaft making sure the marks made in step 6 line up, also make sure thrust washer goes back on.
To reassemble distributor, reverse procedures in steps 5 and 6.
Step 10: Install Distributor Back Onto Cylinder Head.
Distributor coupling is offset and will only go back on one way properly (photo 1 and 2).
After sliding distributor back onto cylinder head it may be necessary to move shaft clockwise and counterclockwise by wiggling distributor rotor in order to match coupling with camshaft groove (photo 3).
Before installing distributor cap back on pay attention to metal spring inside ignition coil (photo 4).
In some cases, harness connectors must be connected together before harness can slide onto bracket (photo 5-7).
Match marks made to distributor and cylinder head at the end of step 1, this will keep timing in the correct setting.
Reverse removal procedure in step 1.