Selami Kumru

Beiträge von Selami Kumru im Blog von RSS Kumru Automotive.

Drawing: a thin jet of oil leaves a pinhole in the body of a hydraulic hose that is fixed to the machine with two clamps, hits a piece of cardboard standing beside the hose and leaves a stain; no hand holds the cardboard; the magnifier shows the pinhole in the hose wall and the point where the jet comes out

10. Oktober 2026Hydraulikschläuche

Hydraulic fluid injection injury: why a pinhole leak is dangerous and what to do in the first hour

A jet of oil under pressure can pierce skin. Why the wound misleads, what to do at once and how to look for a leak, from HSE and DGUV guidance.

Drawing: two brake pipe ends side by side, shown cut down the middle; on the left a double flare, an open funnel whose rim is folded inward into two layers, on the right a bubble flare with a domed end, each with a nut slid onto the pipe behind it; the magnifier shows the domed end held in a double flare port, with the gap left between them marked in red

5. Oktober 2026Stahlrohre

Brake line flare types: SAE double flare vs DIN / ISO bubble flare

A brake pipe ends in an SAE double flare or a DIN / ISO bubble flare. How to tell them apart, why they do not mix, and which flaring mistakes leak.

Drawing: the path of the fuel, left to right: tank with a vent hole in its cap, suction pipe, lift pump bolted to the engine (priming lever on top, glass sediment bowl and strainer underneath), filter and injection pump; the outlet pipe of the lift pump is disconnected and fuel runs from the outlet into a container; the magnifier shows the inside of the pump: spring, diaphragm, inlet and outlet valves, with a split in the diaphragm marked in red

3. Oktober 2026Einspritz- und Kraftstoffleitungen

Diesel lift pump: what it does and how to tell when it is failing

What a diesel lift pump does, the symptoms of a failing one, flow and pressure tests from two tractor manuals, and how to tell pump from line.

Drawing: side view of a brake pipe and its line nut screwed into the end of a brake hose; a flare-nut wrench sits on the nut, the rust ring where the nut meets the pipe is marked in red, and a straight marker line is drawn along the pipe, with a red arrow beside it for the case where the pipe turns too; the magnifier shows two wrenches side by side: the open-end wrench presses on only two flats of the nut, the flare-nut wrench wraps almost all the way round it

23. September 2026Stahlrohre

How to free a seized or rounded line nut on brake, fuel and turbo oil lines

A seized line nut is freed in order: clean, soak, flare-nut wrench, tighten a touch first. If the pipe turns or the nut rounds off, cut and replace the pipe.

Drawing: a short hydraulic hose assembly; both ends are seen from the side: the ferrule crimped onto the hose, with lengthwise die marks, and the fitting below it; the right-hand end sits between the two jaws of a pair of calipers: the jaws hold the crimped ferrule from both sides; the magnifier shows the same ferrule between the caliper jaws, with an arrow from jaw to jaw marking the crimp diameter

20. September 2026Hydraulikschläuche

How is a hydraulic hose assembly made? Skiving, crimping and checking the crimp

A hydraulic hose assembly is cut, skived, crimped and measured. Which ends need skiving, how the crimp diameter is checked, how the assembly is tested.

Drawing: two brake pipes side by side, held to the chassis by clips; the coating of the upper steel pipe has blistered in places and the pipe is covered in red rust patches, while the surface of the lower copper-nickel pipe is clean; the magnifier shows the steel pipe in cross-section: rust has started where the coating is broken and the pipe wall has thinned there

13. September 2026Stahlrohre

Copper-nickel or steel? Brake line materials and corrosion

Brake pipes are coated steel, copper-nickel or stainless; plain copper is never used. Where steel pipe rusts and how inspection grades the corrosion.

Drawing: four injectors side by side on top of an engine; a clear hose runs down from the return port on top of each injector into one of four clear chambers hanging side by side in front of the engine; in three chambers the fuel stands at the same level, in one it is clearly higher, and that chamber and its injector are marked in red; the magnifier shows the push-fit return connector on top of an injector with its clip and O-ring, and diesel seeping from the joint and dripping down the side of the injector

8. September 2026Einspritz- und Kraftstoffleitungen

Injector leak-off line: what it does, why it leaks, and when the injector is to blame

When a common-rail leak-off line leaks, check the clip and O-ring first. How a leak-off test is done, how to read it, and where the sources disagree.

Drawing: two hydraulic hoses in side view, one above the other; the body of the damaged upper hose is wrapped in tape and held by two clamps, oil drips from the edge of the wrap, and a red cross stands next to it; the new hose assembly below has a crimped fitting at each end, with a blue tick next to it; the magnifier shows the edge of the wrap: the tear in the cover and the wire braid are still there under the tape, and oil seeps out of the tear

4. September 2026Hydraulikschläuche

Can you repair a hydraulic hose? When a repair is acceptable and when it is not

A hydraulic hose is not patched or spliced. Used ends stay out of a new assembly; tape and clamps are for low-pressure hose only, until it is changed.

Drawing: two bends of the same steel tube side by side, seen from the side; on the left a wide-radius bend with an arrow from the centre of the arc to the tube centerline showing the bend radius, on the right a tight-radius bend whose outer arc has collapsed inward and whose inner arc has wrinkled, both marked in red; the magnifier shows the cross-section of the tight bend: an oval ring instead of a round one, thin on the outer side and thick on the inner side

28. August 2026Stahlrohre

Tube bend radius: minimum radius, ovality and wall thinning

Bend radius is measured to the tube centerline and stated in tube diameters. Bend too tight and the tube flattens, thins outside and wrinkles inside.

Drawing: four hose ends side by side, seen end-on, each with a different clamp on it: a worm-drive clamp with its screw housing and screw head, a spring clamp with its two ends bent outward, a T-bolt clamp with its bolt and nut, and an ear clamp with its ear crimped shut; under each one its name and the hose it is found on; the magnifier shows, in a side view cut down the middle, the bulge on the fitting the hose slides over and the clamp seated just behind it

24. August 2026Hydraulikschläuche

Hose clamp types: worm-drive, spring, T-bolt and where each one is used

Worm-drive, spring, T-bolt and ear clamps: which hose each one holds, why a clamp works loose and when it can be reused, with figures from maker documents.

Drawing: the path of the fuel in a single row, left to right: tank with the lift pump inside, filter, high-pressure pump and fuel rail; the needle of the gauge on top of the rail sits below the mark for the desired pressure; the low-pressure side from the tank to the pump is framed in blue as the place to check first, and the high-pressure pump is left for last; the magnifier shows a filter blocked with dirt, with little fuel coming out

19. August 2026Einspritz- und Kraftstoffleitungen

P0087, fuel rail pressure too low: what to check on a common-rail diesel, and in what order

What P0087 means, when it sets, and the order of checks on a common-rail diesel: filters, low-pressure line, lift pump, pipes and injector return.

Drawing: two unions side by side at the same scale, shown cut down the middle; on the left a flared union, with the flared ends of two brake lines seated inside it behind the nuts; on the right a compression fitting, where only a ferrule ring squeezes each plain line end; the magnifier shows the ferrule and the plain line passing through the nut, with an arrow beside the line showing the direction in which it can separate

17. August 2026Stahlrohre

How to splice a brake line, and can you use a compression fitting on one?

Compression fittings do not belong on brake lines. A splice is cut back to sound tube, flared and joined with a flared union. What inspection rules say.

Drawing: a side view of the tractor’s rear hydraulic outlet facing the tip of the hose from the implement, with a red cross in the gap between them; the cylinder at the other end of the hose lies on the ground, warming in the sun; the magnifier shows the hose tip in section: the oil in the hose presses the check valve onto its seat and holds it shut

14. August 2026Hydraulikschläuche

Hydraulic coupler won’t connect: how to relieve the pressure trapped in the hose

A coupler that won’t connect has oil under pressure behind it. How to relieve it on a tractor or skid steer, and why not to strike the tip.

Drawing: four fitting ends in section, side by side: banjo, tapered thread, flat face with O-ring, flared cone; on each one the place where it seals is marked in the same blue: the two washers on the banjo, the thread itself on the tapered thread, the O-ring in the face on the flat-face end, the cone faces on the flare; the magnifier shows two cones whose threads engage but whose angles differ, with a thin gap left between them

11. August 2026Verschraubungen und Auswahl

Hydraulic fitting types: JIC, ORFS, BSP, NPT, metric, and 37° versus 45° flare

A fitting is identified by where it seals, not by its thread. JIC, ORFS, BSP, NPT and metric ends, why 37° and 45° flares do not mix, how to measure.

Drawing: side view of a section of an excavator boom and the boom cylinder; two hydraulic hoses run from the machine body to the cylinder. The upper hose leaves its fitting straight, its clamp sits on the straight section, the bend starts after that and the lay line on the hose runs straight. The lower, red hose is bent tightly directly behind its fitting and its lay line spirals; the magnifier shows oil spraying from the hose where it has burst at this tight bend

4. August 2026Hydraulikschläuche

Why do hydraulic hoses burst on an excavator, and how do you replace one?

Why hydraulic hoses burst on an excavator, and the order for replacing one: relieve the pressure, remove, route, bleed the air and check for leaks.

Drawing: a fuel pipe running over the hot exhaust manifold on the side of an engine; diesel leaking from the fitting in the middle of the pipe drips onto the manifold, which is drawn in red and gives off heat; in the corner an inspection sheet with one line marked with a cross; the magnifier shows the drop hanging under the fitting and a piece of cardboard held beneath it to find the leak, with a wet patch on it

30. Juni 2026Einspritz- und Kraftstoffleitungen

Is a diesel leak dangerous, and will it pass inspection?

A diesel leak can ignite on hot parts and, under pressure, penetrate skin. How the MOT manual and Turkey’s defect table class it, and what to do.

Drawing: a banjo joint in section; a hollow banjo bolt passes through the ring end of the pipe and screws into the housing, with a washer on each face of the ring, and the oil comes from the engine along the pipe and through the bolt into the housing; the magnifier shows a new washer above an old one that took the imprint of the faces when it was tightened

16. Juni 2026Verschraubungen und Auswahl

Banjo bolts, washers and gaskets: copper or aluminium, reuse, and sealant

Banjo bolt washers are renewed every time, in the specified material, with no sealant. Copper versus aluminium, annealing, and why no general torque exists.

Drawing: two lengths of hydraulic hose of the same type, one above the other, one thin and one thick; a line of print, drawn as small boxes, runs along each of them; the pressure gauge beside the thin hose reads high and the one beside the thick hose reads low; the magnifier shows the four boxes of the layline: type, size, working pressure marked in red, and date of manufacture

2. Juni 2026Verschraubungen und Auswahl

How to read a hydraulic hose pressure rating: what the layline tells you

The layline gives type, size and working pressure. What 1SN, 2SN and 4SP mean, how pressure changes with size, and whether a 3000 psi hose will do.

Drawing: the path of the fuel on a diesel engine, left to right: tank, filter with a bleed screw on top, high-pressure pump, fuel rail and injector; the low-pressure side from the tank to the pump is marked, and the nut of the high-pressure line running from the fuel rail down to the injector is marked in red; the magnifier shows fuel with bubbles coming out around the loosened bleed screw

4. Dezember 2025Einspritz- und Kraftstoffleitungen

How to bleed a diesel fuel system after a filter or line change

Mechanical pump: bleed screw, hand primer, then the line nuts. Common rail: the electric pump fills the system and the high-pressure lines stay tight.

Drawing: two hoses taking the same turn, one inside the other, each with a fitting at both ends; the upper one, a steel-braided PTFE hose, passes a hot part that gives off heat and takes the turn in a wide bend, while the rubber hose below takes the same turn more tightly; the magnifier shows a PTFE hose bent too sharply, in section: the liner has collapsed inwards at the bend and narrowed the passage

4. November 2025Verschraubungen und Auswahl

PTFE hose or rubber hose? Temperature, fluid, bending and service life

What temperature a PTFE hose takes, why it kinks, why fuel needs a conductive liner and how long it keeps on the shelf, set against rubber hose.

Drawing: the suction side of a fuel system, left to right: tank, the pipe leaving the tank, a rubber hose with two clamps, filter, a clear hose and the pump; the loose clamp, the crack in the hose and the filter seal are marked in red, blue arrows show air getting in at those points, and bubbles travel along the clear hose towards the pump; the magnifier shows air being drawn in through a hairline crack in the wall of the hose, with bubbles in the fuel

30. Oktober 2025Einspritz- und Kraftstoffleitungen

Air in a diesel fuel line: hard starting caused by pipes and hoses

When air keeps coming back, look for a leak: hoses, clamps, filter seals or the return line. The symptoms, and four ways to find where it gets in.

Drawing: a high-pressure pump on the left, an injector on the right and, between them, a jacketed fuel pipe that looks like one thick pipe; a window opened in the pipe shows the thin high-pressure pipe inside it and a crack in that pipe; a thin leak-off line runs from the lower end of the pipe down to a small collecting tank, and a red alarm lamp is lit beside the tank; the magnifier shows the cracked high-pressure pipe, the outer pipe around it and the fuel from the crack staying inside the outer pipe

26. August 2025Einspritz- und Kraftstoffleitungen

Jacketed (double-wall) fuel injection pipes on marine diesel engines: what SOLAS requires

SOLAS wants the high-pressure fuel pipes between pump and injector jacketed. The rule’s wording, which ships it covers, the 375 kW exception and upkeep.

Drawing: an injection pump on the left and four injectors in a row on the right; one line runs from the pump to each injector, the line to the near injector loops around on its way and the line to the far injector goes straight there; below, the same four lines are drawn straight with their ends level, all four the same length; the magnifier shows a shortened line that does not reach its seat, leaving a gap

15. Juli 2025Einspritz- und Kraftstoffleitungen

Why are injector lines the same length? Can they be shortened or bent?

Why injector lines are made the same length, and why they are not shortened or bent: Bosch’s rule on line dimensions and Perkins’ advice on fitting.

Zeichnung: eine gerissene Einspritzleitung vom Rail zum Injektor, mit einer Hülse als Flicken versehen, doch unter dem Flicken tropft weiter Diesel; darunter wartet eine neue, gleich gebogene Leitung darauf, ihren Platz einzunehmen; die Lupe zeigt den Flicken im Schnitt: der Riss geht von der Innenwand durch die ganze Wand der Leitung nach außen, und der Flicken bleibt außen

6. Mai 2025Einspritz- und Kraftstoffleitungen

Lässt sich eine gerissene Kraftstoff- oder Hydraulikleitung reparieren?

Gerissene Einspritzleitungen werden ersetzt. Warum Schweißen, Hartlöten und Verschraubungen versagen und was bei Zulauf-, Rücklauf- und Hydraulikleitungen gilt.

Zeichnung: eine gebogene Einspritzleitung vom Rail zum Injektor, mit einer Schelle in der Mitte; die Lupe zeigt einen Riss, der direkt hinter der Überwurfmutter beginnt

11. März 2025Einspritz- und Kraftstoffleitungen

Warum reißen Einspritzleitungen?

Nicht durch Druck, sondern durch Ermüdung: Schwingung, Montagespannung, Werkstoff. Schellen, Montagefolge und warum eine gerissene Leitung nie repariert wird.

Drawing: a single hydraulic hose in side view, gently curved, with a fitting at each end; three signs of damage are marked in red along it, from left to right: a section where the cover is worn away and the wire braid shows, a blister, and fine cracks; the magnifier shows the right-hand end: the hose has slipped out of the ferrule, leaving its old seat exposed, and a drop of oil hangs at the end of the ferrule

11. Februar 2025Verschraubungen und Auswahl

When to replace a hydraulic hose: the failure signs

The signs that a hydraulic hose must be replaced and what causes them, DGUV’s 6-year guide value, and why a leak is never traced by hand.

Drawing: an injector line running from the fuel rail to the injector, with diesel dripping from behind the nut at the injector end; the magnifier shows the inside of the nut: the cone on the line sits in its seat metal to metal, with no gasket, and a scratch on the sealing face lets the fuel out

15. Januar 2025Einspritz- und Kraftstoffleitungen

Injector line leaking at the nut: tighten, clean or replace?

More torque is not the fix. Check the torque once, then the sealing faces and the alignment; on common rail fit a new line. The order of work.

Zeichnung: dasselbe Stahlrohr in vier Zuständen von oben nach unten, mit Pfeilen zwischen den Schritten: ein gerades, auf Länge geschnittenes Rohr; das Rohr mit aufgeschobenen Überwurfmuttern und einem angestauchten Kegel an jedem Ende; das gebogene Rohr; die fertige Leitung mit einer Kappe an jedem Ende. Die Lupe zeigt das Rohrende im Schnitt: den angestauchten Kegel, dahinter die Überwurfmutter und die innen offen gebliebene Bohrung

13. August 2024Einspritz- und Kraftstoffleitungen

So wird eine Diesel-Einspritzleitung hergestellt: vom Stahlrohr zum fertigen Teil

Wie eine Einspritzleitung entsteht: nahtloses Stahlrohr, Schneiden, Kegel, Biegen, Autofrettage, Beschichtung und Reinigung, mit dem Grund jedes Schritts.

Drawing: an injector line removed from the injector and pulled back, its cone facing the empty seat in the injector; the magnifier shows a new cone above a used cone: the used one is marked and its bore has narrowed

13. Juni 2024Einspritz- und Kraftstoffleitungen

Can injector lines be reused once they have been removed?

On common rail most makers want a new pipe every time; on older mechanical engines a sound pipe goes back. How to judge the cone and when to scrap the pipe.

Drawing: a fuel rail on top of the engine with steel high-pressure pipes running down to three injectors; the union of one pipe is wet, diesel has pooled at the foot of that injector, and a fine mist and a smell rise above the union; the diagnostic tool beside the engine shows no fault code; the magnifier shows a hairline crack in the pipe right next to the union, with diesel seeping from it

20. Februar 2024Einspritz- und Kraftstoffleitungen

Common-rail pipe leak: symptoms and what to do

A leaking common-rail pipe shows as diesel smell, wet fuel or mist, sometimes with no fault code. Symptoms, risk and the order of work from maker documents.

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