LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

HELP! Oil pressure drops to zero when braking hard!!!

Thread Tools
 
Search this Thread
 
Old 07-19-2003, 04:49 PM
  #1  
Registered User
Thread Starter
 
bad96firechikin's Avatar
 
Join Date: Oct 2002
Location: Fairmount, GA
Posts: 327
HELP! Oil pressure drops to zero when braking hard!!!

Ok guys, I noticed this happening for the first time today on the way to work. I hit the brakes hard, and suddenly saw my "Check Guages" light on. This is the first time I've ever noticed this. On the way home, I tried it again. Sure enough, under hard braking, the oil pressure will drop to zero, everytime. I did just change the oil today, but it got it's usual 5 quarts. Should I maybe try to overfill it? The dip stick shows that it is full. I do have the stock oil pan, but have rebuilt the motor, and I went with a brand new Melling High Volume oil pump. Is is possible that so much oil stays in the block b/c of the HV pump, that not enough stays in the pan, and when I brake it sloches away from the pick up tube? I'm lost. I cannot continue to have this problem though. Any suggestions are welcomed. Thanks!
bad96firechikin is offline  
Old 07-19-2003, 04:52 PM
  #2  
Registered User
 
shoebox's Avatar
 
Join Date: Dec 1969
Location: Little Rock, AR
Posts: 27,714
There is the possibility that the oil pickup tube has come off the pump.
shoebox is offline  
Old 07-19-2003, 04:57 PM
  #3  
Banned
 
thewinner's Avatar
 
Join Date: May 2003
Posts: 1,090
sounds like the pickup is being uncovered cause the oil is all going to the front of the pan. or as shoebox said, maybe it fell off, you should always weld those on.
thewinner is offline  
Old 07-19-2003, 04:58 PM
  #4  
Registered User
Thread Starter
 
bad96firechikin's Avatar
 
Join Date: Oct 2002
Location: Fairmount, GA
Posts: 327
Crap....any instructions on the easiest way to drop the pan in the car?
bad96firechikin is offline  
Old 07-19-2003, 05:41 PM
  #5  
Registered User
 
Kreinmc's Avatar
 
Join Date: Feb 2001
Location: Mesa, Az
Posts: 622
pull motor.
Kreinmc is offline  
Old 07-19-2003, 06:05 PM
  #6  
Registered User
Thread Starter
 
bad96firechikin's Avatar
 
Join Date: Oct 2002
Location: Fairmount, GA
Posts: 327
pulling the motor isn't going to cut it.
bad96firechikin is offline  
Old 07-19-2003, 06:37 PM
  #7  
Banned
 
thewinner's Avatar
 
Join Date: May 2003
Posts: 1,090
not sure how you are gonna get it out without at least raising the motor a bit since its so close to the kmember
thewinner is offline  
Old 07-19-2003, 06:45 PM
  #8  
Registered User
Thread Starter
 
bad96firechikin's Avatar
 
Join Date: Oct 2002
Location: Fairmount, GA
Posts: 327
I don't mind raising it a bit...but I don't want to pull it again. The motor has been out of the car more than it has been in it.

I'd like to add that the car holds 50-60 PSI oil pressure at idle, and almost 80 PSI while driving.

Last edited by bad96firechikin; 07-19-2003 at 07:06 PM.
bad96firechikin is offline  
Old 07-19-2003, 08:07 PM
  #9  
Registered User
Thread Starter
 
bad96firechikin's Avatar
 
Join Date: Oct 2002
Location: Fairmount, GA
Posts: 327
Before I go to the trouble of dropping the oil pan, I can't help but think that maybe there is a connection to me changing my oil today. I know I put in 5 1/2 quarts, and I know I didn't double-gasket the filter. I also ran the car last night at the track, and I wonder if there is a connection there also. Any suggestions?
bad96firechikin is offline  
Old 07-19-2003, 09:39 PM
  #10  
Registered User
 
RichJ's Avatar
 
Join Date: Jul 2002
Location: Great Falls, VA
Posts: 202
That really sounds like the pick-up fell off Maybe this would be a good time to switch to a tubular k-member
RichJ is offline  
Old 07-19-2003, 09:58 PM
  #11  
Registered User
 
shoebox's Avatar
 
Join Date: Dec 1969
Location: Little Rock, AR
Posts: 27,714
Originally posted by bad96firechikin
Before I go to the trouble of dropping the oil pan, I can't help but think that maybe there is a connection to me changing my oil today. I know I put in 5 1/2 quarts, and I know I didn't double-gasket the filter. I also ran the car last night at the track, and I wonder if there is a connection there also. Any suggestions?
If you drained your oil and then rapped with a mallet on the bottom of the pan, you might hear the pickup rebounding inside, if it is laying on the bottom. If you hear it rattling around, then you know it fell off. If you don't, it may or may not be. It's not a foolproof test, just a suggestion.
shoebox is offline  
Old 07-19-2003, 10:11 PM
  #12  
Registered User
Thread Starter
 
bad96firechikin's Avatar
 
Join Date: Oct 2002
Location: Fairmount, GA
Posts: 327
I appreciate the advise Shoebox. I did an interesting experiment a little earlier. I first got the car to speed, then slammed the brake and held the clutch, and of course the oil pressure fell to zero again. The next several times, I got the car to speed, threw it in neutral, and held the engine at 3000 RPM and 80 PSI oil pressure, while I slammed the brake and brought the car to a halt. The oil pressure never dropped past the 40 PSI mark in all of my attempts. If this were a problem with the pick-up tube coming uncovered, shouldn't the pressure fall of quicker if it is holding constant at 80 PSI when the car comes to a halt? I know the car did not have this problem this morning before I changed the oil. I'm going to change the filter tomorrow, and see if by some wierd freak accident it is related to the filter. Who knows.
bad96firechikin is offline  
Old 07-19-2003, 10:54 PM
  #13  
Registered User
 
RCF925's Avatar
 
Join Date: Jan 2001
Posts: 608
Just in case you have to pull the pan I just did mine after dropping in new 385 and had 2 rods hitting the pan. You don't have to pull motor, just jack it up 3 inches, In my case I also lowered the K-Member a 1/2" and then the pan came out. Good Luck
RCF925 is offline  
Old 07-19-2003, 11:30 PM
  #14  
Registered User
Thread Starter
 
bad96firechikin's Avatar
 
Join Date: Oct 2002
Location: Fairmount, GA
Posts: 327
Originally posted by RCF925
Just in case you have to pull the pan I just did mine after dropping in new 385 and had 2 rods hitting the pan. You don't have to pull motor, just jack it up 3 inches, In my case I also lowered the K-Member a 1/2" and then the pan came out. Good Luck
Ha! Was your car in Gm High Tech Performance?!?! Cool...Recognized it from your sig. Anyways, I've decided I'm just going to get an engine cradle to hold it up from the top side, then I'll loosen the K-member. Will I have to brake the brake lines loose, or is there enough slack in them that I won't?
bad96firechikin is offline  
Old 07-20-2003, 03:09 AM
  #15  
Registered User
 
kclarson's Avatar
 
Join Date: Apr 2002
Location: Eau Claire, WI, USA
Posts: 20
Exclamation

I had the same problem with my 97 Camaro. I went under the car and pounded on the oil pan with my fist and heard a clank every time. I ordered a happy hooker from TPIS, lifted the motor high enough to pull the oil pan and fixed the oil pump pickup. Good Luck!!

Courtney
kclarson is offline  


Quick Reply: HELP! Oil pressure drops to zero when braking hard!!!



All times are GMT -5. The time now is 07:42 AM.