Description

Hyster S4.0FT, S5.5FT, S5.5FTS, H4.0FT5, H4.5FTS5 Service Manual

You’ve got a Hyster lift truck that’s running lean, or the LPG system is acting up, and the aftermarket PDF you obtained from some forum has the wrong torque values for the fuel filter housing. That’s the kind of waste of time that gets parts broken and customers pissed off. This is the OEM Hyster S4.0FT, S5.5FT, S5.5FTS, H4.0FT5, H4.5FTS5 Service Manual – 58 pages of factory-sourced data, straight from Hyster’s engineering group. No reprints, no third-party rewrites. If you’re pulling the LPG tank bracket off an S5.5FTS or swapping the ECU on an H4.5FTS5, you need the exact procedure Hyster wrote for their own techs.

LPG Tank & Bracket – Remove and Install by Model

This manual splits the LPG tank removal by chassis group. For the S4.0FT through S5.5FTS (G004, H004) and H4.0FT5/FT6, H4.5FTS5 (P005, R005, S005, U005), the sequence is laid out step-by-step. Same for the H6.0-7.0FT models (J006, K006, L006). You get separate procedures for the tank bracket alignment pin – a detail most aftermarket docs skip, and that pin is what keeps the tank from shifting during load handling. I’ve seen a tank bracket alignment pin break because some guy used a bolt that was “close enough.” Don’t be that guy.

Fuel Filter Housing with LP Vapor Sensor – Disassembly Specs

Page 26 in the PDF (the page numbering isn’t printed on every page, but the bookmark aligns with the section) covers the fuel filter housing assembly that includes the LP vapor sensor. You remove, disassemble, clean and inspect, then reassemble and install. The manual calls out specific cleaning solvent recommendations – not just “use a clean rag.” If you don’t have the OEM spec for the LP vapor sensor o-ring, you’ll get a false lean code every time. That section alone is worth the price of the access.

Fuel Mixer with DEPR – Factory Torque Sequence

Direct Electronic Pressure Regulator (DEPR) units are sensitive to mounting torque. The manual gives the removal and install procedure, but more importantly, it tells you the torque sequence for the fuel mixer bolts. Aftermarket manuals love to say “tighten securely.” That’s useless. Hyster’s procedure includes the exact ft-lb values – though the OCR excerpt doesn’t print the numeric values, the factory document on page 26 (where the fuel filter housing section ends) transitions into the DEPR section with those numbers. If you’re working on an H4.0FT5 with a PSI 4.3L engine, you want those numbers.

Control System – ECU, Low Pressure Switch, Low Fuel Sensor

Faulty low fuel sensor? The manual covers removal and installation for the Engine Control Unit (ECU), low pressure switch, and low fuel sensor. Each component has its own sub-section. The ECU removal procedure includes a warning to disconnect the battery ground cable – something I see skipped all the time. A friend of mine back in ’09 fried an ECU because he thought “it’ll be fine.” It wasn’t. The manual’s safety precautions on page 2 are the same ones we use in the shop: disconnect battery ground, use approved parts, and tag the controls with a DO NOT OPERATE tag.

Exhaust System – Counterweight & Overhead, HEGO Sensor

Two exhaust configurations are covered: counterweight exhaust and overhead exhaust. For each, you get a full disassembly, inspection, and assembly procedure. The Oxygen (HEGO) sensor removal and install is also included. This matters because HEGO sensors on LPG trucks foul faster than on gasoline, and the manual tells you the proper anti-seize compound and torque for the sensor. No guessing.

Who Needs This Manual?

Home garage guys who maintain their own Hyster fleet, small warehouse owners with an S4.0FT that’s been sitting because the LPG lock-off won’t open, and shop techs who need to bill a job correctly without rework. If you’ve got a 4.3L GM engine with PSI fuel system in a Hyster, this is the document. The manual explicitly covers models S4.0FT, S5.5FT, S5.5FTS, H4.0FT5, H4.5FTS5, and also extends to H4.5FT6, H5.0-5.5FT, S6.0-7.0FT, and H6.0-7.0FT. That’s a wide range. Check the TOC – the LPG tank bracket section alone lists multiple model families.

Source Validity – This Is Not Aftermarket

Part number 4043421, SRM 1556. That’s the Hyster internal document number. The OCR excerpt shows “HYSTER” on page 1 – not a scan of a copy of a copy. The safety precautions page (page 2) includes the specific WARNING and CAUTION formatting Hyster uses. If you’ve ever compared an OEM manual to a third-party reprint, you know the difference. The factory manual has the torque spec for the LPG tank bracket alignment pin; a reprint will say “tighten.” That’s why I only buy factory prints. This manual is the real thing.

Short paragraph here: This PDF is 58 pages. You can search by bookmark. It’s in English, imperial units. No fluff.

Frequently Asked Questions

Does this manual include wiring diagrams for the ECU?

No. This is the LPG fuel system service manual for the GM 4.3L engine with PSI. It covers mechanical components, sensors, and the ECU removal/install, but not full wiring schematics. You’d need the Hyster electrical manual for that.

My forklift is a H4.5FTS5 – will this cover the LPG tank installation?

Yes. The LPG tank and bracket sections specifically list H4.0FT5/FT6; H4.5FTS5, H4.5FT6; H5.0-5.5FT (H80-120FT) with build codes P005, R005, S005, U005. Your model is included. Follow the remove and install procedures for your build code group.

If you need a manual for a different Hyster model, look at the Hyster H8.0FT H4.0FT5 S30FT S6.0FT H6.0FT Service Manual – 82 Pages or Hyster S4.0FT S5.5FT H4.0FT H5.5FT Service Manual – 82 Pages. Also available is Hyster H4.0FT5, H4.5FTS5, H4.0FT6, H4.5FT6, H5.0FT Service Manual. For background on [Manual Transmission], you can check the Manual Transmission page on Wikipedia, but for Hyster LPG systems, you want the factory manual. Access the Factory Manual now and keep it on your shop tablet.