Škoda 706 RTO: legendary Czech truck - technical data, repairs and modernization

Truck Škoda 706 RTO - one of the most recognizable and popular models of the Czechoslovak automobile industry, produced from 1961 to 1983. This medium-duty vehicle became a symbol of the era, serving both the national economies of socialist countries and being exported to dozens of countries around the world. Despite his venerable age, 706th family is still actively used in the CIS countries, Africa and Latin America due to its simple design, maintainability and the ability to adapt to modern requirements.

In this article we will analyze in detail technical specifications all modifications Škoda 706 RTO, including engines, transmission and chassis. We will pay special attention unique design features that distinguish this truck from its Soviet counterparts (ZIL-130, GAZ-53) - for example, a synchronized gearbox and independent front suspension on some versions. You will also find step-by-step repair instructions, lists of common faults and tuning recommendations to improve power and comfort.

Technical characteristics of the Škoda 706 RTO: engines, transmission, payload

Basic model Škoda 706 RTO equipped inline 6-cylinder diesel engine volume 11.78 l (modifications 706 RT and 706 RTO). Power varied from 130 to 180 hp. depending on the version and degree of forcing. The transmission was a manual 5-speed (late models) or 4-speed (early models), with synchronizers in all forward gears, which was rare for trucks of that time.

The carrying capacity of the standard version was 8–10 tons, but there were also specialized modifications:

- 706 RTO-Z — truck tractor (gross train weight up to 26 tons);

- 706 RTS — dump truck with a lifting capacity of 7 tons;

- 706 RTO-MT — version for tropical climates with enhanced cooling.

Feature 706 RTO was independent front suspension on wishbones (in later versions), which provided better handling compared to spring counterparts. The braking system is pneumatic, with drum mechanisms on all wheels. Electrical equipment is 12-volt (later 24-volt on export versions).

Typical faults of the Škoda 706 RTO and how to fix them

Despite the reliability, Škoda 706 RTO There are a number of “diseases” associated with age and design features. Here are the most common problems:

• 🔧 Compression drop in cylinders — wear of piston rings and liners. Solution: boring the block to repair dimensions or sleeve. Original spare parts can still be found in the Czech Republic or Poland.
• 🔥 Engine overheating - clogged radiator or faulty thermostat. In tropical versions (706 RTO-MT) a reinforced radiator with an oil cooler was installed.
• ⚙️ Difficulty shifting gears — wear of synchronizers or gearbox bearings. Early models (pre-1970) did not have synchronizers in 1st and 2nd gears.
• 🛞 Play in the steering — wear of ball joints or steering linkage. With independent suspension (706 RTO-P) silent blocks fail more often.

⚠️ Attention: When replacing piston rings with Škoda 706 RT be sure to check the gap in the locks - it should be 0.4–0.6 mm. Exceeding this value leads to ring sticking and oil burn.

Another common problem is fuel leak from injection pump. In original pumps Bosch PE 6 A70 plunger pairs often wear out. Repair is possible, but it is cheaper to install a remanufactured pump from LIAZ or Tatra (they are interchangeable with minimal modifications).

How to check compression without a compression gauge?

Remove the injectors and manually crank the crankshaft using the starter. If noticeably less air escapes from one cylinder than from the others, there is low compression. The method is approximate, but allows you to quickly localize the problem.

Repairing the Škoda 706 RT engine: step-by-step instructions

Engine overhaul Škoda 706 RT - a labor-intensive task, but doable in a garage if you have the tools. Below are instructions for a standard 6-cylinder diesel engine with a volume of 11.78 liters.

Drain the oil and antifreeze|Remove the cylinder head|Check the cylinder head plane for curvature|Disassemble the connecting rod and piston group|Clean the block from carbon and deposits-->

Step 1. Removing the engine

Disconnect all pipes, electrical wiring and high pressure pipes. Remove the gearbox (after draining the oil). Use a hoist or winch - the weight of the engine without attachments is ~800 kg. Engine to frame mounting - 4 bolts M16×1.5.

Step 2. Disassembly and troubleshooting

After removing the pan and flywheel, measure:

- Cylinder diameter (nominal - 120 mm, wear limit - +0.15 mm);

- The gap in the main and connecting rod bearings (tolerance - 0.08–0.12 mm);

- Crankshaft runout (maximum 0.03 mm).

When boring a block for repair pistons (+0.5 mm, +1.0 mm) keep in mind that the sleeves Škoda 706 — “wet” type (removable). They can be replaced separately from the block.

Step 3. Assembly and running in

When assembling, use new gaskets (original or from LIAZ 100) and sealant Loctite 574 for flanges. Run-in should take place without load:

- The first 500 km - no higher than 2000 rpm;

- The next 1000 km - up to 2500 rpm.

Check the oil pressure (normal is 3–4 kg/cm² at idle speed).

💡

Before installing the pistons, lubricate them and cylinders with graphite lubricant - this will make the first start easier and reduce the risk of scuffing.

Tuning Škoda 706 RTO: how to increase power and comfort

Modernization Škoda 706 RTO can serve two purposes: power increase (for cargo transportation) or increased comfort (for daily use). Let's consider both directions.

Engine tuning

• 🔥 Turbine installation - based on the original 706 RT you can assemble a turbodiesel with a power of up to 220 hp. Suitable turbines from Cummins 6BT or Deutz BF6M.
• ⚡ Replacing the injection pump - pump Bosch PE 8 P110 from Tatra T3 allows you to increase the injection pressure to 200 bar (versus 160 bar in stock).
• 🛢️ Common Rail system - extremely costly, but realistic. Kits from Denso for trucks from the 90s.

Transmission upgrade

The weak point of the stock gearbox is lack of synchronizers in 1st and reverse gears (in early models). Solutions:

- Install a 5-speed gearbox from the later ones 706 RTO (fully synchronized);

- Put the box from LIAZ 100 (direct replacement, but requires clutch adapter).

Comfort and safety

• 🪑 Seats from modern trucks — chairs suitable from Scania 90s or MAZ-5336 (with modification of fastenings).
• 🔦 LED optics - in the headlights H4 LED lamps can be installed Philips X-tremeUltinon (does not require modifications).
• 🎵 Multimedia - head unit Pioneer DEH-S4200BT with Bluetooth fits into a standard place without modifications.

⚠️ Attention: When installing the turbine on Škoda 706 RT Be sure to strengthen the oil pump and cooling system. A standard radiator will not cope with the thermal load, which will lead to detonation and destruction of the pistons.

Electrical equipment Škoda 706 RTO: diagrams and repairs

Electrical diagram Škoda 706 RTO built on the classic principle: 12-volt system (24 V on export versions) with a generator Pal 28V 50A and relay regulator RR350. The main problems are related to contact oxidation and wiring wear.

Typical faults:

• 🔋 Battery undercharge - the relay regulator or diode bridge of the generator is to blame. Check the voltage at the battery terminals at 2000 rpm (should be 13.8–14.4 V).
• 💡 Turn signals don't work - most often the relay burns out RS503 (analogue from VAZ-2101 fits without modifications).
• 🔌 Short circuit — check the insulation of the wires under the panel (especially in places of friction with metal).

For diagnostics, use the electrical diagram (shown below in a simplified form). The original diagrams can be found in Škoda Trucks archive or on owner forums.

+-----------[Battery]-----------+
|           12V/24V        |
|                          |
[Generator] [Starter]
|           RR350          |
|                          |
+---------[Fuses]-------+
|         |
[Headlights] [Dashboard]

When replacing a generator, a unit from LIAZ 100.42 (power 65A), but the pulley mounting will require modification. You can also install a modern generator Bosch 14V 90A (article 0 124 520 015), but with a pulley adapter.

Where to buy spare parts for Škoda 706 RTO: trusted suppliers

Find original spare parts for Škoda 706 RTO It’s not easy today, but it’s possible. Here are verified sources:

Parts type	Supplier	Website/Contacts	Notes
Engine (liners, pistons, crankshafts)	Czech Republic (Czech Republic)	ceskedily.cz	Original and remanufactured parts
Transmission (gearbox, clutch)	LIAZ Service (Slovakia)	liazservice.sk	Interchangeable spare parts from LIAZ
Electrical equipment	Autoelektro (Poland)	autoelektro.pl	Generators, starters, relays
Body panels	Retro Trucks (Germany)	retro-trucks.de	Reproductions of the hood, fenders, cabin
Tuning (turbines, intercoolers)	Diesel Power (Ukraine)	dieselpower.com.ua	Kits for boosting diesel engines

To search for used spare parts, we recommend the following sites:

- eBay Germany (search by request "Skoda 706 RT Teile");

- OLX Poland (section "Części do ciężarówek");

- Facebook groups: "Škoda 706 & LIAZ Owners Club".

⚠️ Attention: When purchasing a used engine Škoda 706 RT Be sure to check the block number (stamped on the back wall). Engines before 1975 have weaker liner walls and cannot be bored to repair sizes.

Legal aspects: registration and operation of the Škoda 706 RTO in 2026

Operation Škoda 706 RTO in Russia and the CIS countries is associated with a number of legal nuances. The main problem is lack of certificate of conformity (since the model is discontinued). However, there are legal ways to legalize a truck:

• 📄 Import as a "retro car" — if the truck is more than 30 years old, it can be imported as a “historical vehicle” (RF Government Decree No. 413).
• 🚛 Conversion for special equipment — design as a “self-propelled vehicle” (category D) through Gostekhnadzor.
• 🔧 Replacing the engine with a certified one - for example, on Cummins ISF3.8 (there is a certificate for trucks up to 12 tons).

To pass the technical inspection you will need:

1. Replace the glass with triplex (according to GOST R 51709-2001);

2. Install seat belts (even if they were not in the original);

3. Modernize lighting (LED or halogen instead of incandescent).

In Belarus and Kazakhstan the rules are more loyal - there Škoda 706 can be registered as a “truck over 30 years old” without additional modifications. In Ukraine, there is a simplified procedure for “vintage” cars (Ministry of Internal Affairs Order No. 600).

FAQ: Frequently asked questions about the Škoda 706 RTO