Parts for your 1991 Mitsubishi Pajero-Clutch master cylinder

1991 Mitsubishi Pajero clutch master cylinder — fitment, purpose and servicing

Yes, a clutch master cylinder is relevant to the 1991 Mitsubishi Pajero — on manual-transmission models. Technical references that cover the 1991 L040 (late Gen I) and early V20 (Gen II) Pajero note a hydraulic clutch system comprising a clutch master and slave cylinder. These include: Mitsubishi factory Workshop Manual, Group 21 Clutch (details the hydraulic circuit and bleeding procedure), Mitsubishi ASA/CAPS parts catalogue listings for “Master Cylinder, Clutch” for 1991 Pajero/Montero variants (with VIN-dependent part numbers), and the Haynes Mitsubishi Pajero/Montero 1983–1996 manual, which describes inspection and bleeding of the clutch master cylinder on Gen I/II vehicles. Automatic Pajeros don’t use a clutch master cylinder, as no clutch pedal is fitted.

On a 1991 Pajero with a manual box, the clutch master cylinder is the bit that turns pedal effort into hydraulic pressure. Press the pedal and a piston inside the master pushes brake fluid (DOT 3 or DOT 4) down a hard line to the slave cylinder on the bellhousing, which moves the clutch fork to disengage the clutch. It sits on the firewall (driver’s side), with a small reservoir feeding it. When it’s healthy, pedal travel is smooth and bite point is consistent, when it’s tired, the pedal can feel spongy and gear changes get cranky.

Good servicing makes a big difference. Fresh fluid every two years or around 40,000 kilometres keeps moisture and corrosion at bay. Owners should inspect the reservoir level and colour under the bonnet, look for dampness around the pushrod boot inside the cabin (firewall side), and check the line and unions for weeping. Any regular top‑ups suggest a leak somewhere in the system. If the pedal sinks, feels airy, or the bite point wanders when hot, the internal seals may be on the way out.

Replacing the master cylinder is a tidy weekend job for a competent home spannerer, but protecting paintwork is key — clutch fluid is brutal on paint. A flare-nut spanner helps crack the line cleanly, and bench‑bleeding the new master before installation speeds up final bleeding. It’s smart practice to replace the slave cylinder and soft hose at the same time, they age together and this saves a second bleed later. After fitment, bleed at the slave, keep the reservoir topped, and finish with a pedal free‑play and height check as per the workshop manual. While under the dash, it’s worth inspecting the pedal box, clevis pin and bush for wear, and giving the pivot a light lube. Do that, and the old Pajero’s clutch action stays light, predictable and happy on both road and track.

• Common symptoms of a failing master: fluid loss, damp firewall or pedal boot, spongy pedal, difficulty selecting gears, rising or inconsistent bite point.

FAQs — 1991 Mitsubishi Pajero clutch master cylinder

What brake fluid should be used in the Pajero’s clutch master cylinder?
DOT 3 or DOT 4 brake fluid is appropriate. Many owners prefer DOT 4 for its higher boiling point, but mixing types isn’t recommended. Flush the system every two years to reduce moisture build‑up and internal corrosion.

How is the system bled after replacing the master cylinder?
Bench‑bleed the new master first, install it, then bleed at the slave cylinder. Keep the reservoir topped, use slow pedal strokes, and watch for clean, bubble‑free fluid. A vacuum or pressure bleeder can make the job quicker and cleaner.

Do automatic 1991 Pajeros have a clutch master cylinder?
No. Only manual‑transmission models use a hydraulic clutch with a master and slave cylinder. Automatics don’t have a clutch pedal or clutch hydraulics.