Threw away $150 on a cheap injection pump rebuild kit

I bought one of those no-name rebuild kits off Amazon for my old Cummins 12 valve. Figured it was the same as the Bosch parts just without the logo. After I put it all back together the pump started leaking from the head seal within like 50 miles. Had to pull the whole thing apart again and do it right with a genuine Bosch kit the second time. Anyone else get burned by cheap injection pump parts?

3 comments

3 Comments

the_susan12d agoMost Upvoted

Thing is, those cheap kits often skip the step of properly lapping the plunger and barrel. The tolerance on those parts is so tight that any tiny irregularity from a sloppy finish will cause immediate failure. People focus on the seals but the real issue is the lack of quality control on the mating surfaces themselves.

sandraflores12d ago

Hell yeah, that's the truth. Honestly, I had the same thing happen on a old Ford 7.3. I wasted a weekend with a cheap kit and the plunger just didn't feel right in the bore. Tbh, I ended up taking it to a local shop that just did the lapping properly with the original parts and new seals from Bosch. Ngl, it cost me a little more but it's been running strong for three years now with no leaks. You really can't skip that step, the fit has to be perfect or you're just asking for trouble.

williamb2912d ago

Honestly, my buddy learned this exact lesson the hard way on his 24 valve. He grabbed a cheap kit off eBay thinking he was being smart saving fifty bucks. Ngl, he spent a whole weekend putting it together and was so proud until he fired it up and saw fuel pissing out right where the head seal goes. Took him two more weekends to tear it down, clean everything again, and do it with the real Bosch parts. Tbh, he said the cheap kit's plunger felt rough right out of the box compared to the OEM one. He keeps telling everyone now that injection pumps are not where you cheap out, it's just not worth the headache.