[DruMor]

I have a 2008 VF4 with 300psi TSC. I think the TSC pump is getting weak. This machine has ran A LOT of cast iron thru it. I have one tool in particular that I get a low TSC pressure alarm on. On this tool I am flushing coolant thru the collet to wash away chips, so I understand that the pressure will be lower than say a drill with small passages. I have ran this same program and same tool since the machine was brand new and it never had this problem until yesterday. We have added pressure gauges to this machine and with this tool the TSC system shows about 50 psi. With no tool in the spindle and TSC on it shows about 40. A 6" long 1/4" drill shows about 130 psi, and I swear it used to be much higher than that (I'm thinking well over 200 psi).

I cleaned the sump screen and replaced the TSC filter. The pressures didn't come up any but it did run about another day before the problem came back.

About what pressure should I be seeing with no tool in the spindle, TSC running?

We also have a pressure gauge rigged up to mount into an ER32 collet. With this in the spindle (yes, I know dead heading pump is bad but I only ran it a couple seconds) it read 150 psi.

[Jim Dawson]

Sounds like a worn pump. But possibly take a look at the pressure relief valve (on the pump). May have crud on the seat and thus is partly open. In any case, it's time to pull the pump apart and check it out.

[DruMor]

Follow up to original post:

To say the pump was worn out is an understatement. The housing really wasn't worn, but both shafts were worn badly which let the gears wear funny. To band aid it back together to get the machine back up and running we made a new idler gear shaft (which was worn the worst, about .025" clearance) and put it back together. It's a little noisy, but it builds a lot more pressure than it did.