300Tdi Injector Spill Rail / Leak-Off Kit — Fitting Guide
Fitting instructions for the Land Rover 300Tdi PTFE-lined stainless steel spill rail / leak-off kit. Please read this guide fully before fitting — the leak-off circuit must be air-tight for the engine to start and run correctly.
Thank you for choosing a Pioneer 4x4 spill rail kit. This assembly returns excess fuel from the tops of the injectors back to the injection pump, replacing the original perishable rubber leak-off pipes. Everything needed to fit the kit is supplied in the box. Take your time, keep everything clean, and work through the steps below in order.
- PTFE-lined stainless steel braided spill rail / leak-off assembly
- Double banjo bolts for injectors No.2, No.3 and No.4
- Single banjo bolt for injector No.1
- Stainless steel copper-sealing washers for every banjo joint
- Two fuel-line compression fittings (nut & olive) — one to suit the original Land Rover fuel lines, one to suit the Pioneer 4x4 fuel line kit
- Make sure the engine is cool and switch off / isolate the fuel supply before removing the old pipes
- Have a clean rag to hand and catch any diesel that weeps as the old leak-off pipes come off
- Lay the new spill rail out and check it against the engine before fitting, so you can see which end goes to injector No.1 and which returns to the pump
- Keep all the supplied copper washers together — you need every one of them to seal the joints
- Route the rail so it sits clear of the exhaust, moving parts and sharp edges
Numbering the injectors
The engine has four injectors in a row along the top of the head. Injector No.1 is the one closest to the front of the engine, with No.2, No.3 and No.4 following on behind it towards the bulkhead.
The spill rail connects the leak-off port on top of each injector and then returns to the injection pump. Because of the way the rail loops from one injector to the next, the end injector and the middle injectors take a different number of banjos — which is why two types of bolt are supplied.
Injector No.1 — single bolt
Injector No.1 sits at the end of the rail and takes only one banjo, so it uses the single banjo bolt. Seal it with a copper washer either side of the banjo:
- Copper washer under the bolt head
- Banjo
- Copper washer against the injector
Injectors No.2, 3 & 4 — double bolts
These injectors carry two banjos each (the rail arrives and leaves), so they use the double banjo bolts. The two banjos are sandwiched together, and a copper washer must go between them:
- Copper washer under the bolt head
- First banjo
- Copper washer between the two banjos
- Second banjo
- Copper washer against the injector
On injectors No.2, No.3 and No.4 it is easy to forget the copper washer that sits between the two sandwiched banjos. Leave it out and that joint will weep and draw air, causing hard starting and rough running. Every banjo face must have a copper washer against it.
| Location | Bolt | Banjos | Copper washers (from bolt head down) |
|---|---|---|---|
| Injector No.1 | Single | 1 | Washer · banjo · washer |
| Injector No.2 | Double | 2 | Washer · banjo · washer · banjo · washer |
| Injector No.3 | Double | 2 | Washer · banjo · washer · banjo · washer |
| Injector No.4 | Double | 2 | Washer · banjo · washer · banjo · washer |
| Injection pump | Original M12 | 1 | As original — re-use the pump's own washers |
Re-use the original M12 banjo bolt
The return end of the rail connects to the M12 banjo on the injection pump. You must re-use the original pump banjo bolt here — do not fit one of the supplied bolts in its place.
The original bolt contains a non-return valve that keeps the leak-off circuit primed and stops fuel draining back. Losing or swapping this bolt will cause starting and running problems, so keep it safe when you remove the old pipework and refit it with the new rail.
Compression fittings — pick the right one
Where the fuel line connects to the tail on the large banjo at the injection pump, the kit supplies a compression fitting — a nut and olive. Two are supplied because the fuel line itself differs from vehicle to vehicle, so you fit whichever matches yours:
- Smaller nut & brass olive — for vehicles still running the original Land Rover fuel lines
- Slightly larger nut & olive — for vehicles running the Pioneer 4x4 fuel line kit
Fit the one that matches your fuel line onto the tail of the large banjo at the pump. If you're not sure which you have, get in touch before fitting.
The banjo bolts thread into the injector bodies. Take care not to over-tighten them. The copper washers only need to be nipped up to seal — go gently and stop as soon as the joint is snug. Over-tightening can strip the injector, crush the washers or distort the banjo, and puts the injector at risk. Firm and sealed, not forced.
- Double-check every banjo has a copper washer against each face, and that No.2, No.3 and No.4 have the washer between the sandwiched banjos.
- Fit the correct fuel-line compression fitting to the tail on the large banjo at the pump.
- Confirm the original M12 non-return bolt is refitted on the pump.
- Prime and bleed the fuel system following the vehicle manufacturer's procedure until the engine starts and runs cleanly.
- Run the engine and check every joint carefully for fuel weeps or air leaks. Re-check again after a short run once everything is up to temperature.
- Make sure the rail is routed clear of the exhaust and any moving parts, with no strain on the hose.
Lifetime warranty
Every Pioneer 4x4 stainless steel kit carries a lifetime warranty against corrosion and component failure, except where damage results from:
- Incorrect installation or over-tightening
- Misuse or competitive driving
- Failure to follow the supplied instructions
Pioneer 4x4 accepts no liability for engine damage, fuel leaks or personal injury resulting from improper installation or use. If you are not confident carrying out the work, have it fitted by a competent diesel specialist.
If you're unsure, ask
If you're ever unsure about fitting or vehicle suitability, please contact us before starting the job.
Email pioneer4x4@outlook.com · Tel 01404 643149 · www.pioneer4x4.com