Howto: Bleed the clutch on a classic Ford Ranger
Bleeding the clutch on a Ranger is kind of a whole process. It doesn't work to do it the way you might have learned elsewhere, and for the love of god don't reverse bleed it. Following a mechanic donking mine all up and filling the lines with bubbles, I spent quite some time identifying a correct, manageable, and effective process for bleeding the clutch on a Ranger.
This should apply to any manual Ranger or Mazda B, from 1993 through 2011. The broad strokes likely also apply to earlier models, but having never owned or worked on one I don't know for sure.
Overview of the system
The clutch pedal controls the clutch actuation by way of a very simple hydraulic system. There's a master cylinder connected directly to the clutch pedal, which drives fluid through one line to a slave cylinder inside the bell housing under the truck. There's a reservoir under the hood above the master cylinder, and a bleed valve under the truck on the side of the bell housing.
Everything outside the bell housing can be removed with a ratchet set and a screwdriver. I would also recommend buying the specific tool for disconnecting the hydraulic line underneath the truck. It's not strictly necessary, as you can finagle it off with a screwdriver. The tool is much easier though, only costs like $5, and will keep you from damaging the little plastic ring that allows the connector to release. Don't break that ring on the quick connector, you'll have a fun adventure ahead if you do.
The problems you'll encounter
Master cylinder orientation
The primary problem with bleeding these clutches is the orientation of the master cylinder. It's mounted in the driver-side wheel well, with the plunger pointed upwards into the cab and directly connected to the pedal. This is nice in some ways. It means there's no complex linkage to break, loosen, or bind. So the clutch feel is good, and doesn't decay as a linkage wears or a cable stretches. It makes the master cylinder completely impossible to effectively bleed while it's installed though. If a bubble gets in there, you cannot get it out by bleeding the system while it's fully installed.
Bubble trap in hydraulic line
Behind the frame the line curves up to form an upside-down U. This bubble trap seems intended to keep bubbles from making it from the bleed valve up into the master cylinder. That's a good idea, in light of the master cylinder's orientation. It means you need to flush fluid through with some gusto, though, if you want to get bubbles out of that U.
If a bubble has found its way into this part of the line, you probably won't get it out with a simple gravity bleed. You'll need to aggressively pump the clutch with the bleed valve open, to move the fluid through fast enough to get a bubble down the back side of the U. Doing that means you need a helper though, to make sure the reservoir doesn't empty, because then you'll pull air into the master cylinder and need to start all over.
1) Disconnect and remove everything
- Disconnect and remove everything from the truck. You'll have to take out the wheel well plastic, which is kind of a bastard to put back in, but it must be done.
- Unclip the clutch pedal from the master cylinder in the cab. There's a little plastic clip that you can get off with a flathead screwdriver.
- Remove the master cylinder from the firewall. You need to grab it in the wheel well and turn it a quarter turn and it will come right out.
- Remove the clips holding the line to the frame and the reservoir in the engine bay.
- Unhook the quick disconnect next to the bell housing.
2) Bench bleed everything you just took out
- Hang everything you just took out by the reservoir.
- Starting at the bottom, tap all along the hydraulic lines with a screwdriver. Manipulate the lines the whole way so that any bubbles can travel up to the reservoir. Make sure to also turn the master cylinder plunger-side-down and tap it really well.
- Tap until there are no bubbles coming up into the reservoir, and the plunger is rock hard if you try to depress it.
3) Reconnect everything
- Do what you did in step 1 in reverse.
- Try your clutch. If it works well, you're done.
- If it still doesn't work very well, there is probably a bubble in or around the slave cylinder, and you'll have to flush it out.
4) Flush the system aggressively
For this step you will need:
- about 6-8 feet of hose that fits over your bleed valve (I think 1/4" or 5/16" ID should work)
- fresh DOT 3 brake fluid
- a helper (but only for a couple minutes)
To flush the system, you're going to hook a hose onto the bleed valve, route it back into the reservoir, get it all filled up with brake fluid, and pump like mad for a while.
- Hook the hose up to the bleeder valve, with a wrench over it so you can open and close it
- Run the hose up to the reservoir, and prop it up so it will drain into the reservoir
- Have your helper make sure the reservoir doesn't get empty while you open the bleeder and pump until the hose is full and pushing fluid into a full reservoir
- Your helper is done, they can go
- Pump the clutch fast for a few minutes, until you don't see any bubbles in the hose
- Close the bleeder valve and see how it feels. If the clutch is stiff you're done. Otherwise open it again and pump some more.
This process should eventually give you a functioning clutch, despite Ford's best efforts to make a clutch hydraulic system that is as difficult as possible to bleed.