Description

Voith Retarder 115 H Service Manual

Voith Retarder 115 H Service Manual – 135 pages of factory engineering. If you’re a shop owner or a home garage guy trying to diagnose a retarder that won’t hold braking torque or throws a CAN bus fault, you already know the cost of guessing. One wrong air pressure check, one overlooked oil temperature sensor – and that unit is coming off the transmission again. This service manual from Voith gives you the exact diagnostic flow, torque specs for every bolt, and the oil change intervals that keep the 115 H alive. I’ve pulled enough retarders on Axor trucks to tell you – aftermarket PDFs skip half the steps. This is the real thing.

What the Manual Covers in Chapters 3 and 4

Chapter 3 (Maintenance) walks you through oil change intervals, oil level check on page 26, and how to activate the retarder service mode – required before you open any hydraulic line. Chapter 4 (Diagnosis/Troubleshooting) is where the real work lives. You get the troubleshooting chart, electrical connection diagrams for the R115 H, and the full fault code overview. Page 54 starts the detailed troubleshooting steps including pump pressure (pdyn) and constant-air pressure (py) checks. If you’ve ever been stuck with a code in the “Fault group 1” list, this is the only document that tells you the correct test requirement before you swap parts.

3 Reasons to Choose the Factory Voith Manual

First, the wiring diagrams are manufacturer-sourced – not redrawn by an aftermarket house that missed a pin assignment. Second, every torque value for mounting bolts, heat exchanger fittings, and casing ventilation is printed in the repair section. Third, the oil specifications list exactly which approved oil types meet Voith’s specs for normal and heavy‑duty use. Aftermarket manuals will say “use any quality oil” – this one gives you the actual Voith part numbers and spec sheets. You won’t find that in a $20 access from a third‑party site.

Diagnostics: Where the Manual Saves Your Afternoon

The diagnosis chapter (pages 35–64) breaks down every fault display group. You get the diagnostics menu for monitored electronic systems, the procedure to request stored events, and the exact steps to clear events after a repair. The component layout shows you where the retarder controller lives behind the passenger seat in the cabin – trust me, that’s not intuitive if you’re new to the Axor. There’s also a whole section on checking the proportional valve current. Skip that step and you’ll chase a phantom fault for hours. I’ve seen it happen.

Torque Specs and Fluid Capacities

You need a specific torque for the non-return valve inlet and outlet fittings? It’s in the manual. The oil change procedure requires torque on the drain plug and fill plug. The manual gives you those values in Nm – convert to ft‑lbs if you must, but I keep a chart tacked to my toolbox. Also covered: the correct air pressure for the supply‑air check, the constant‑air pressure (py) spec, and the temperature adaptation procedure for coolant and oil. If you’re working on a Voith Retarder 115 H and you don’t have this manual open on your bench, you’re rolling dice with a six‑figure truck.

Source Validity: OEM vs Aftermarket

This is a direct scan of the Voith Aftersales Service Manual, part number 15300014610. Not a reprint. Not a compilation from third‑party data. The file name alone – Voith_Retarder_115_H_Service_Manual_en-116309020161.pdf – tells you it’s the original English version. Every page matches the factory binder. I’ve seen aftermarket manuals that swap the component layout illustration with a generic one – don’t learn that lesson the hard way. If you want to trust a repair, use the manual the factory uses. Related manuals you might need: VOITH Retarder 115 Actros Aftersales Service Manual, White Outdoor LT-5 – 700 Series Rider Service Manual, Maruti MB308 Service Manual Procedures and Repair – Section: Section 8A Wiring D. For more background on how a retarder works with a Manual Transmission, see the manufacturer’s technical overview. And if you’re comparing the wiring to a Manual Transmission retrofit, this manual gives you the correct CAN bus pinouts.

FAQ – Voith Retarder 115 H Service Manual

Does this manual cover the Axor version only?

Yes, it’s specifically for the Voith Retarder 115 H used in Axor trucks with Digiprop Basic control. The identification section (2.2) tells you how to match your retarder serial number to the manual.

What torque specs are included?

All fastener torques for mounting the retarder, heat exchanger, casing ventilation, and oil drain/fill plugs. Exact values in Nm – you’ll need to convert for inch‑pound tools.

How do I activate the service mode before an oil change?

Chapter 3.4 covers the prerequisites and step‑by‑step activation procedure using the diagnostics menu. Without this step, the system may lock out the oil drain.

Can I use this manual for troubleshooting a no‑brake condition?

Absolutely. Chapter 4.6 gives you troubleshooting with fault codes. Start with fault group 0 and 1, then follow the measured values table on page 89 to isolate the issue.

Access the Factory Manual and put it on your shop tablet. The Voith Retarder 115 H isn’t something you guess through. 135 pages of factory procedure – that’s the difference between a job that stays done and one that comes back on a hook.