Truck headaches all week

[country gent]

Had my diesel excurrsion in to shop for charging issues early this week, first was thought that batteries were bad checked weak under load. Then got it back and went to town for a quick trip and battery light started flashing, back to garage for alternator, got it back today and went for a quick trip to local carry out, lost power stering and power boost to brakes. Brake pedal is till up dosnt go to floor but I have to really push get it stopped. Its the 7.2 turbo diesel 2000 year. Im wondering if the serpintine belt is an issue? Or just bad luck

[blademasterii]

If the belt is present and intact, it isn't the issue. I also don't believe the brakes would be effected with no belt. Sounds like electrical issue, ie wiring. Could be a blown fuse inline between the alternator and batteries. Some of them are rediculously hard to find.

[Cowpoke]

Check the belt tension idler. When the bearing in the idler goes out it can cause all you described, but usually burns the belt off.

[oneokie]

Does it have the mechanical vacuum pump?

[country gent]

Im not sure but believe the diesels had a vacum pump to power the booster and other needs for vacum as diesels dont produce cacums running

[Petrol & Powder]

Given that limited information I'd say those may be unrelated problems.
If that setup uses a tensioner, that's where I would start my diagnosis.

[Johnny_V]

If the serpentine belt goes out (usually, but not always an idler pulley issue) your brakes and steering are affected, causing what you described. We have seen this time and time again when alternators are replaced with cheap units (premature bearing failure), or the belt is installed improperly (Not seated correctly in the grooves of the pulley). Also, when replacing alternators or P/S pumps, all too often spacers/shims are dropped or not reinstalled properly. Have your local Ford dealer check it out.....

[Petrol & Powder]

Im not sure but believe the diesels had a vacum pump to power the booster and other needs for vacum as diesels dont produce cacums running
That's correct. Diesel engines don't have throttles on the intake side, so there's almost no intake manifold vacuum. In order to run vacuum powered devices (power brake boosters, ventilation controls, etc, ) a vacuum pump is utilized to provide the necessary vacuum.
Generally those pumps are driven off of timing gears, cams, cranks, etc. and not belt drives. Sometimes they are belt driven but I don't think they would fail before other accessories on the same belt (water pump, alternator, AC compressor, power steering pump) failed.

[starmac]

Vacuum pump is run off the belt on the earlier ford diesels, nothing electrical is going to affect the brakes. Possible they could have knocked the hose off somehow, but generally if the belt is turning the pump and you have to really oush the brakes and air defaults to defroster it is the vacuum pump.

[Johnny_V]

If I'm not mistaken, these vehicles didn't have any vacuum power brake, but used the Hydro-Boost style of booster. The Hydro-Boost relies totally upon the P/S pump for power assist. If the belt goes, so does the P/S and the brakes, as originally posted.

[starmac]

F 450's had hydroboost, 250's and 350's had vacumn boosters.

[Ford SD]

Had my diesel excurrsion in to shop for charging issues early this week, first was thought that batteries were bad checked weak under load. Then got it back and went to town for a quick trip and battery light started flashing, back to garage for alternator, got it back today and went for a quick trip to local carry out, lost power stering and power boost to brakes. Brake pedal is till up dosnt go to floor but I have to really push get it stopped. Its the 7.2 turbo diesel 2000 year. Im wondering if the serpintine belt is an issue? Or just bad luck

I have a 99 f250 superduty Gas so very close maybe 90% the same

had battery problems, had alternator problems, would not start -- dead battery
head light would flicker with engine running had it checked--- no problem found
light would flicker so fast dignistic machine said everthing was ok( think strobe light fast)
regulator in alternator also went luck had it i had a spare or it would have been 2 alternators in 4 months

I found problem by bypassing key switch (hot wiring it right to the battery with a fuse (one wire) no more strobe light
so I then started digging ---problem was corision where the wires joined at the fuseabale link (main fuse) and split with another fuse to feed the alternator
(around battery box)

engine vibration would cause lights to strobe (turning off charging circut ) so light would see battery voltage 12v then alternator voltage 14v 12-14-12-14 and you could see the 2v diference in the lights-- flicker

electrial problems hardest ones to find

[starmac]

Not familar with the excursion, but if you laos power steering and power on the brakes it must have hydroboost, as your power steering pump powers the power brakes, check the fluid, but if full and your belt is on it, then you are probably looking at a pump. Again it will not be anything electrical.

[Plate plinker]

Vacuum pump. If it has one it's likely the problem. Been there done that on my dodge. Check the vacuum lines for pin holes where it may have rubbed against something. Done that one too.
Do you have you cruise control? Does that work?


Good luck.

[Petrol & Powder]

I don't know enough about a diesel 2000 Ford Excursion to say it has a vacuum brake booster or hydraulically boosted brakes. Determining that would be the first step in diagnosing the OP's problem.
If it does have hydraulically boosted brakes , then the combined steering/brake issue makes sense and the belt/power steering pump would be a logical place to start.
However, I think it is more likely to have a vacuum brake booster. If the vacuum pump is driven off of the serpentine belt, then the power steering & brake issues could be explained by a loose belt (I'd look closely at the tensioner). If the vacuum pump is driven directly off the engine, I'd suspect the pump itself or a massive vacuum leak somewhere.

I'm skeptical that the electrical problem and the steering/brake problem are related. A belt so loose and/or worn that it wouldn't turn the alternator but would turn the power steering pump is unlikely. Not to mention you'd hear it slipping.

[TXGunNut]

F 450's had hydroboost, 250's and 350's had vacumn boosters.

I think the 7.3 had hydroboost in most cases, vacuum boost for gas motors.
Also make sure batteries are fully charged (if they'll take a charge) before testing. It's a basic thing that too many folks overlook but if around here if a battery is more than 3 years old I'll replace it if I have any doubts.

[bnelson06]

7.3 has a vacuum pump in your excursion. That's most likely the problem. Tensioner could also be going bad but that would throw the belt, just had to replace the tensioner on mine this morning.

[starmac]

The 6.9's and 7.3's in pickups had belt driven vacumn pumps and vacumn boosters until you got to the 450's. It is a common brake upgrade to put the hydroboost from a 450 on the 250's and 350's, as it will all bolt on with minimun altering of the bolt holes in some of the master cylinders. I have never played with excursions though, so don't know for certain what setup they have.

[leadman]

I checked the Autozone web site and it lists a hydraboost so it runs off the power steering pump.
A bad tensioner can cause the belt to slip and the brake and electrical issues. There was one version of this engine that the belt could be incorrectly installed and it would look like it was ok unless you followed the belt diagram on the core support.

[geargnasher]

OK, lemme help here.

2000 Ford Excursions with the 7.3L diesel all had hydraulic brake assist. All Ford 7.3L engines from 1999 (Ford didn't make a '98 model at all) until the end of the run did except some of the vans. The only vacuum is supplied by a small electric pump on the passenger fender apron to run a the mode and recirculation door actuators, the turbo wastegate, and on 4x4s the automatic locking hubs.
There are no shims or washers involved with the alternator mounting or spring-loaded tensioner, they simply bolt in place.

Likely losing PS and brake assist simultaneously means the serpentine belt flew off because someone didn't put it back on correctly after the alternator was replaced, but anything could have happened.

Alternators have a pretty high failure rate on those, so no surprise there. Weak batteries or a dead cell in one can kill an alternator fast. Another issue is the small plug on the alternator, it's in an exposed place and gets yanked/tweaked/bent/pulled on when servicing other things in the area, and they have a tendency to break strands in the wires behind the connector, pull out pins, or get a bad connection. Autoparts stores carry replacement "pigtails" for these particular alternators which can be spliced in to solve the problem if the alternator isn't charging like it should. Most Ford-savvy techs will put a voltmeter across the battery terminals and wiggle the alternator harness to make sure it's ok before and after changing an alternator on a 7.3L Powerstroke. Many alternators are replaced when the problem is actually the wiring.

Gear

[country gent]

Well today in the daylight we filled the power steering pump and it has a leak in the one line going forward towards the bumper. But the brakes and steering seemed to come back also so may have had a critter chewing when it was sitting last summer. No whines or growls so far will get it into the shop monday. With the wieght size of the vechicle with out the power assits you need really strong arms and legs to steer and stop it. Garage is only 6-7 miles away so wont be to bad.

[country gent]

May sell it to the one mechanic he wants it and it seems :happier" there also.

[Sgtonory]

If you sell give me a PM would love to have one of those.

[Petrol & Powder]

geargnasher gets first prize for the most informative post in this thread !

[TXGunNut]

geargnasher gets first prize for the most informative post in this thread !


Very true, but if I may add the hydroboost unit on these trucks fail from time to time as well. Glad it was apparently just a fluid leak, those can be expen$ive enough. Good job checking out the basic stuff first, OP!
7.3 Excursions are tough old beasts, lots of folks like them. Basically it's an SUV version of an F250, much like the seldom-seen (unless your work for Uncle Sugar) 2500 Suburban. Downside is many parts are getting hard to find and those that are available may be quite expen$ive.

[geargnasher]

I'm certainly no Ford fan, but those Diesel Excursions are good trucks, really good. I actually have little difficulty finding anything for them at all, and they are becoming very inexpensive to maintain. Fuel injectors and radiators, for example, are VERY cheap these days, as are valve cover harnesses, turbos, chassis parts, and even small parts for the interior. Lots of aftermarket AND dealer support still there.

I seem to recall a power steering cooling loop up inside the left front frame rail that could leak if a small rock got kicked up in there and wore a hole through it and is an absolute BEE-ATCH to replace, but maybe that was on some of the Chevy trucks of the '96-2000 vintage. Those 7.3L truck powerstrokes had a PS system that will burp a pint of oil all over the place if you turn the wheels with the engine off, so watch out for that. They're also tough to get the air out of, just be patient, crank the engine and turn the wheel quickly to a lock and kill it asap. Let it sit for an hour. Do it again, try not to run it more than two-three seconds at a time. Do this four times. That should take care of the moaning/groaning and pulsing/kicking of the hydroboost if it does that when you get it back from the shop.

Gear