Author Topic: Vehicle Question (Read 209 times)

United · « **on:** August 11, 2006, 10:22:52 PM »

I have a 1988 F-150 thats been having some problems lately.

Its been a few months since its been driven, so that may be the issue... but here goes:

When I turn the wheel sharply it makes a hissing sound, like its letting off pressure, and the rpms cut down a lot; almost enough to kill the engine. I've only noticed this while sitting still so its not that much of an issue, but it is annoying.

Here are a few things that you may (or may not) need to know:

Stock Ford 302 V8
5 Speed manual
Had to be jumpstarted to run, but has since started up fine
About a quart of oil low, but not below the min-fill line

DiabloTX · « **Reply #1 on:** August 11, 2006, 10:31:51 PM »

Sounds like you are turning the steering all the way to the "stop". It's somewhat normal to have those symptons you describe, especially considering the vehicle. Check the power steering pump fluid and make sure there is nothing binding or hindering the wheels as they turn through the wheel wells. I've seen where people have put on tires bigger and what the car was designed for and had a combination of problems caused by this situation.

United · « **Reply #2 on:** August 11, 2006, 10:40:02 PM »

Well, if I was turning it all the way to the stop then I would understand it a little more... but Im talking about just a half a turn or so. It also doesn't happen if I turn the wheel slowly, just a fairly quick snap. Its almost like the steering is trying to keep up with my input.

Tires are also the stock size, so I dont think thats the issue.

I'll check the fluid, that probably should've been my first guess.

:EDIT: By "quick snap" I mean just doing a 90 degree turn from one street to another, same turning speed.

eagl · « **Reply #3 on:** August 12, 2006, 02:33:42 AM »

Sounds like you may have a steering problem (duh

)

For an easy fix, you could try changing out the power steering fluid first. If you're not mechanically inclined though, then you may just be better off taking it to a shop. Changing out all of the PS fluid involves removing the low pressure return from the pump, starting the car, and turning the wheel full left and right until all the fluid is out. You can help flush it by pouring in some new fluid as you drain it, but that may not be necessary and it would cause you to run the pump longer with no fluid in it, which is probably a bad thing in the long run. Then turn off the car, replace the hose, fill the PS pump, restart the car, and slowly turn the wheel full left and right a few times as you have someone top off the PS reservoir until it stays up at the full line.

At least that's how I've seen it done... Dunno how the pros do it but just draining the fluid out of the pump reservoir only swaps out maybe 20% of the fluid in the system. Again, if you're not comfortable doing this, have a pro do it.

Check all the hoses and power steering rack. If it's leaking, that could cause those sounds as air bubbles work through the system and the PS pump cavitates.

A bad PS pump or even an old belt could do it because when you rapidly turn the wheel, it puts a lot of strain on the PS pump and the drag on the belts increases a lot. With old fluid or a pump with bad seals, the pump could cavitate and make noise.

If you're lucky, new fluid will work. If not, then your next cheapest thing to try is replacing the power steering pump. If the hoses are leaking or cracked, replace those too. If you have to replace the whole power steering or have a leak in the power steering rack, then you're going to get stuck for a fairly hefty repair bill.

I have had a very small leak in the low pressure return side of my power steering rack for about 4 years now, and I'm not doing anything about it because it doesn't really hurt anything but it would cost about $800 to replace the rack with a refurbished unit. As it is, the only time I notice it is occasionally when turning the wheel rapidly past center when driving very slowly, the steering wheel will hang up and jerk a bit at the exact center. I can live with that, it hasn't gotten any worse in 4 years, and it leaks only a couple of drops a month so it's not worth the $800+ repair.

eagl · « **Reply #4 on:** August 12, 2006, 02:38:22 AM »

By the way, it's possible to overload the power steering in many passenger cars with rapid and repeated turns. I had an old ford fairmont and at normal road speeds, I could completely lock up the power steering by jerking the wheel left-right-left about 30 deg each way off center. Lots of modern cars still have low volume systems that will lock up like this.

My firebird is built to avoid this sort of thing and it holds up well when racing hard, but the design of the PS results in quite a bit of pressure in the PS pump and reservoir so it bubbles out a few CC each lap. I have to top it off after a day of racing. I don't think it's boiling out but it does leak a bit.

DiabloTX · « **Reply #5 on:** August 12, 2006, 02:50:41 AM »

Eags, my PS pump has leaked since day one. Just top it occaisionally and all is good. Everytime I take the car in for other service every shop I've taken it to tells me the pump needs to be rebuilt.

Captain Virgil Hilts · « **Reply #6 on:** August 12, 2006, 08:29:28 AM »

It's a fairly common and typical problem with the steering sector and pump on Ford trucks. The solution is to replace them, as well as the hoses (and the cooler, if so equipped).

eagl · « **Reply #7 on:** August 12, 2006, 08:39:40 AM »

Diablo,

Yea, I think the leaking isn't all that big of a deal. Mine leaks a little bit all the time, but when I race it really spews out the filler cap. I don't think it's boiling but PS coolers are a fairly popular aftermarket mod so who knows.

My main concern with the leaking is that if it gets on the belt it could cause slipping and premature wear, but so far it hasn't done that. It just makes things a bit more dirty on that side of the engine as the fluid sprays around a bit and collects dirt.

Eventually I'll need to replace the rack because that really could become a problem someday, but it hasn't gotten any worse and never hangs up anywhere except in parking lots so I'm leaving it alone for now.