Master cylinder or booster?

[NeonVodka [Veteran Member]]

I'm in the process of rebuilding "Filthy Few" after that nasty tumble I took last week. Considering all the dents and bangs she picked up, the truck seems in pretty good shape. Engine is KIA, but I was going to replace it anyway.

Thing is, I know I have to replace the mastery cylinder, but I'm not sure if I should go ahead and replace the booster too since it looks horrible. I keep hearing a whooshing sound in the cab when I first cranked her up (before the wreck) and I figured air was getting past the seals in the booster and causing my engine to idle too low. It might also explain some of the smoke I had when I first cranked.

All I know is if I lose power, my brake pedal goes rock hard. Rather scary when you're rolling downhill through an intersection.

**Off Topic**
I guess while I'm here, could any of you gents also give some advice as to what could be causing me to have low oil pressure? I know the oil pan gasket needs replacing and the carb needs a gasket between the air filter an itself. Could I be losing the oil pump? Before the wreck it tended to hang in the extreme lower end of normal, but when I accidentally added to much oil it read in the midrange. Even more odd, I had good oil pressure going down the road, but setting at idle my pressure would drop to nothing and the truck would stall. Was this due to having too much oil before I was able to catch it and drain it?

[mike327 [Veteran Member]]

When you lose power you lose vacuum, from what you describe I would change both.

Oil pressure is determined by bearing clearance. When you are up to speed the oil pump puts out more volume than can bleed off past the bearings. clogged screen can also cause problems, as well as pump drive. In 30 years of pulling on wrenches and rebuilding engines I have never seen a oil pump be the culprit of low oil pressure,

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If you have a 2.9 the oil pump screen is notorious for getting clogged which would starve the pump of oil.

[Reserector [Veteran Member]]

When you lose power you lose vacuum, from what you describe I would change both.

Oil pressure is determined by bearing clearance. When you are up to speed the oil pump puts out more volume than can bleed off past the bearings. clogged screen can also cause problems, as well as pump drive. In 30 years of pulling on wrenches and rebuilding engines I have never seen a oil pump be the culprit of low oil pressure,

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If you have a 2.9 the oil pump screen is notorious for getting clogged which would starve the pump of oil.

[NeonVodka [Veteran Member]]

Ah, alright. I'm glad I went ahead and ordered both the cylinder and the booster. I'm sure compact car drivers everyone will breath a sigh of relief.

Now the engine I'm working with is a 2.8 L, V6. I may go ahead and take a look at the screen because the truck sat for God knows how long before the guy before me started "working" on it and driving it around. That's what most of the issues I had before were coming from.

So would it be a safe assumption to go ahead to replace the pump drive and possibly the screen? I have a feeling that the bearings may be something a bit beyond my mechanic skills and will probably have to be taken to a shop.

Oh, and the truck leaks, but I'm pretty sure that's because the oil pan gasket is ruined. If it's in any shape like the valve cover gaskets, that could be a cause in an of itself. But how in the world would I figure out what size bearings I need to get?

[Redwood [Veteran Member]]

While you're in there, replace the oil sender. A crapped out sender will make your gauge read low. May not fix it, but it's too cheap and easy to skip.....

[mike327 [Veteran Member]]

If you go so far as change the screen might as well change the pump, they are to cheap and to much work not to. You are more than likely going to need to pull the engine. I dont think the pan will drop down far enough to change the pump or bearings. There is no easy or cheap fix for the problems you describe. Find a junkyard engine, build it, then swap all your accesories.