In our work, we are daily engaged in testing components and spare parts for injectors and diesel pumps from the be t brands available on the market. With our professional equipment and specific kits for disassembling and reassembling injectors, we can test many models of refurbished diesel injectors using our Made in Italy spare parts. This ensures our customers receive safe, efficient, and top-quality products.

 In this article, we will outline step by step the main processes for disassembling, replacing components, and reassembling Bosch CRIN 4.2 Injectors, which are fundamental components in Bosch diesel fuel systems. For injector cleaning and verification, we used the specialized equipment developed by REDAT S.p.A., followed by testing on our workshop’s test bench.

 

You can watch the full process of assembling, disassembling, and testing the Bosch CRIN 4.2 injectors in this video.

https://www.youtube.com/watch?v=PQAOxeylaYY

1. DISASSEMBLING BOSCH CRIN 4.2 INJECTORS

The disassembly of an injector begins with removing the O-rings using a hook tool. Next, the injector is placed in a vise using a securing block. After removing the nozzle nut with a specific wrench, the internal components of the injector can be extracted, such as all the parts inside the bushing. This operation must be performed with precision tools such as pliers and appropriate wrenches. Special care should be taken with the solenoid assembly: using a dedicated wrench, the solenoid nut is removed, allowing the solenoid assembly to be taken out of the injector body.

Warning: We recommend NOT disassembling the solenoid assembly to avoid damaging the delicate internal electrical wires.

Once fully disassembled, the injector undergoes thorough cleaning. It is during this stage that any worn components—such as springs, O-rings, filters, valves, the pumping group, and the nozzle are identified and replaced with high-quality REDAT-branded spare parts.

2. REASSEMBLING THE CRIN 4.2 INJECTOR

 Injector assembly requires the same level of attention and precision. The injector is clamped again in the vise with the securing block, and the solenoid group is reassembled using specialized wrenches to ensure proper torque. The reassembly of the bushing follows, using specific plates and pliers, as well as assembling the nozzle a crucial step to ensure proper injector system function. For mounting the nozzle, a shim adjustment set is used to correctly calibrate the element. Finally, the operation is completed by tightening the nozzle nut and inserting the O-rings and flame trap, restoring the injector to its original, fully reassembled state.

3. DISASSEMBLY AND REASSEMBLY OF THE FILTER IN BOSCH CRIN 4.2 INJECTORS

 A key step in maintaining the CRIN 4.2 injector is the disassembly and reassembly of the filter. Using specialized tools, the filter is removed without damaging the component, and later reinserted with precision into its housing. The professional equipment developed by REDAT SpA is also designed for the filter mounting and dismounting operations on the Bosch CRIN 4.2 injector.

 

Here is a detailed description of the disassembly process:

 - Screw the threaded bushing onto the injector body feed connector.

- Screw the tap guide bushing onto the previously mounted threaded bushing.

- Insert the tap into the tap wrench and then into the guide bushing.

- Thread the filter as far as possible (lubrication is required during this process to avoid seizing between the tap guide and the filter).

- Remove the tap guide and unscrew the guide bushing.

- Screw the extractor nut onto the threaded pin, then screw the whole assembly into the previously created thread inside the filter.

- Screw the extractor nut against the threaded bushing until the filter comes out of its seat.

- At this point, the filter is disassembled and ready for cleaning.

4. TESTING INJECTORS ON THE TEST BENCH

After reassembly with cleaned or replaced components, the Bosch CRIN 4.2 injector must be tested on a dedicated test bench. At REDAT’s workshop, the test is performed on a Hartridge Sabre CRi Expert test bench with dedicated equipment. This machine allows for monitoring the efficiency of multiple injector models (previously selected in the machine's software) through an automated system that checks all the critical functionalities of the component.

 

The test results, displayed by a color code (green for positive result, red for negative result), provide an immediate evaluation of the injector’s performance.

https://www.redat.com/it/news/notizie/redat-lancia-il-suo-isp-tester-per-solenoidi-e-piezo

https://youtu.be/NOyQdmqOgHw?si=O8v7ZCQgSkAFaW2m

                                                           

5. REDAT SPA, COMPLETE SOLUTIONS FOR BOSCH INJECTOR MAINTENANCE

 

REDAT S.p.A. is a reference point in the diesel injector maintenance sector, offering an extremely vast catalog of high-quality spare parts for Bosch injectors and many other major brands. The historic Piedmont-based company also develops specialized equipment for assembling and disassembling components, used by our own workshop technicians. Efficiency, precision, and reliability are always guaranteed when it comes to REDAT-branded products.

 

Thanks to extensive experience in the aftermarket sector, the company is perfectly capable of supporting professionals and operators with advanced technological solutions and highly qualified technical assistance.

 For more information on the range of spare parts available for diesel engines from the world’s leading brands, visit www.redat.com or contact our customer service team.