Injector pop tester - call it crazy but would it work?
 

If I can connect a hardline and a pressure gauge to the bleeding nipple port of a caliper, can I use it as a pop tester? It has a ready reservior of fluid and I just ask someone to pump the brake and I look at the pressure and the spray pattern. Would the master cylinder create enough pressure? Am I crazy?

When done, just bleed the brake and the car is good to go. It should be similar to doing a brake hydraulic pressure test.

HE!! YEA IT'LL WORK!!!

Except that brake fluid has the wrong viscosity, you need diesel or a special oil to calibrate the injectors. Not a bad thought, though.

isn't there a different resistance for popping brake fluid versus popping diesel?

You will need a very strong leg. No where near enough pressure.

A cylindrical cylinder of diesel can be put in line. If there is not enough pressure then all bet is off.

Came across this thread, brake pressure is in the order of 2000PSI. More then enough. If it is not a crazy idea then I will fabricate one, time permitting.

http://www.stu-offroad.com/suspension/bpress/brake-pressure.htm

HAHAHAHAHAHAHAHAHAHAHAHA no

Let us know if it works!

I think it'd be kind of a pain making pop testing a two man job, but what about using a master cylinder as another option for a home built pop tester.

Fluid incompatibility might be a showstopper.

It is not so much a PITA, 2 men job, husband and wife job. I will not be doing it every day. If I do, I would buy a professional quality pop tester. It is unlikely that it will be used for more than once a year. I may build one just on the odd chance that to replace the nozzles of the SDL.

Putting a small diesel container in line will solve the viscosity issue. This is the least of my worry.

Better check compatibility of the seal in the MC to diesel first. The seals are made for brake fluid which is glycol based and may swell or melt with diesel and be ruined as a MC.

Before you go any further make a rough measurement of the area of the piston in the MC and use the formula Force = Pressure X Area... you might then have a better idea if it will work or not.

Ditto. The question is rhetorical, since there are several factors, regarding Pascal's Law and how it relates to the pressures you are after. First, the average brake pedal has a 5:1 ratio of pressure out vs. in. So for $h!ts and giggles, 100lbs in = 500lbs out on the brake pedal to MC input piston. Add a brake booster and you have made it easier. Then, one must factor the surface area of the primary and secondary pistons of the MC to transfer into output PSI. Third, whatever the output piston is, overall psi is increased according to output piston surface area. A smaller piston acting upon a larger piston will increase pressure, but proportionately decrease piston travel. SO, if anyone is wondering if a MC could be used, then one might answer that question with a "maybe" depending on all these factors, piston sizes, fluid viscosities, etc. and pressure requirements of the pop tester. 3000psi is doable in a brake system. Diesel fuel WILL ruin a MC's seals. Could you build a hybrid system with glycol on the piston input side and devise an output side with a double seal with viton being on the diesel fuel side. As I think more on this, it seems like the hydraulic jack idea would involve less engineering.

The diesel container I have in mind is in line between the brake bleeding port and the hardline to the injector, outside the car. I am not that daft to fill up the brake reservoir with diesel.

The brake fluid probably is OK if I only interested to measure the pop pressure and the pattern is not out of whack. The brake pressure gauge is calibrated up to 5000psi so there is a good chance the pressure will be 135+bar. It is a go for me unless there is a show stopper issue.

No. Liquid is incompressible so both will pop at the same pressure. May need to add a check valve. In any event, it will be a while before I get to it as I have no need to service any injectors yet.

There's ole Blaise Pascal's noodle working for us again.;)

Fluid will be consumed during pop testing. How are you going to keep the 2 fluids from mixing?

All the rest of the post was correct... showing that you actually did not mean to say that psi is increased...but that total force exerted by the piston is increased according to the psi multiplied by the surface area of the piston.

That is correct. PSI would not increase within the hydraulic circuit. Force in terms of physical exertion by the output piston on something would.

Bad idea
 

Stressing the brake system.
Risking brake system contamination.
The risk of sucking air into the brake system.

It is cheaper/easier to buy or build a pop tester.

How to build a diesel injector pop tester
http://www.peachparts.com/shopforum/general-information/224334-how-build-diesel-injector-pop-tester.html

Finally finished my over-engineered pop tester!
http://www.peachparts.com/shopforum/general-information/251435-finally-finished-my-over-engineered-pop-tester.html#post2186902

power steering pump as injector pop tester
http://www.peachparts.com/shopforum/general-information/282524-power-steering-pump-injector-pop-tester.html#post2521649

Easy homemade pop tester
http://www.peachparts.com/shopforum/general-information/251436-easy-homemade-pop-tester.html#post2186930

Diesel injector nozzle POP test pump
http://www.peachparts.com/shopforum/general-information/213112-diesel-injector-nozzle-pop-test-pump.html#post1756633




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Ya, my thought too, pretty creative but not really practical -Could it be done, sure, but should it - prob not. Get an old bottle jack and make a cheap tester boy! Plenty of instructions on this site for that. Btw, today I was at Pacific Fuel Injection with Gus (A legend!) and he popped tested my injectors before my very eyes with his equipment (vast, tech, very complete while decidedly "old school" German in approach -perfect!) His Pop tester, while amazing was still something you could fabricate very cheaply on the fly, bottle jack, old injector line, gauge, and few misc hardware parts, sealer, etc

Good luck, keep that braking system out of this equation!