2WD convert possible?

[Bmwtvboy]

wow, that could be an issue for me,both rear bearing are original. Front were new about 70K miles ago when axles were replaced. Does the fuel pump fail while driving or only when you go to start up? I should find a solid brand replacement I think, mine is original: 01/250k miles. But first I should diagnose why my overflow bottle was practically empty yesterday. Seems fine now, no leaking.

[andrewwynn]

Fuel pump can fail at any time. You can have some warning as the pump can be weak before failure and not provide enough extra pressure to run the siphon jet.

The normal lifespan is 5000 hours with E10 gas maybe it's 5-6000 I forget, but that usually means 130-180.000 miles.

I would not necessarily replace but buy and have on hand pierburg or Bosch pump (just the pump not the whole unit) for when it fails.

Usually the pump ultimately fails at start (attempt). It will eventually wear the brushes to nubs and at one point it will land at a bad spot on the commutator and won't turn.

You can likely get it to start with a firm tap on the top of the tank (to get home without a tow).

[andrewwynn]

Bearings can last forever. I wouldn't preemptively replace them.

Recently I've discovered the main cause of bearing failure is impact. Not time or miles. Pot holes basically.

Hit a pothole especially where it torques the wheel sideways and you could damage your wheel bearing in the first mile of driving.

I replaced all four wheel bearings on wife's X5 now (all failed between 130-170.000), but mine has three original and the right front has been replaced twice. (at maybe 150 and 176,000 mi). The left front needs replacing but I couldn't tell until the noisy right was first replaced.

[oldskewel]

Originally Posted by andrewwynn

Bearings can last forever. I wouldn't preemptively replace them.

Recently I've discovered the main cause of bearing failure is impact. Not time or miles. Pot holes basically...

That fits with my experience as well.

But moreso than potholes, I think the use of hammers when working on suspension components damages bearings. Standard practice industrywide though ... creates more work down the line. Do it all the time, nothing to worry about, the hammers make it so easy and fast, 'nuff said ... Easy to think that way if you only work on other peoples cars where you don't see failures down the line, or if you don't keep you own cars long enough to see the longer term consequences of the impact damage.

I always think of bearing surfaces as being made of glass - i.e., hard, strong, but brittle, when working around them. I'll use pry bars, pullers, and light hammer taps on the right spots - making sure the force is not transmitted through the bearing surfaces.

And I've never ever had a wheel bearing fail on any of my cars (now with an average mileage of around 150k miles in my fleet). And only once about 20 years ago had CV joints fail. Keep bearings greased, clean, and avoid impact and they will outlive most things on any car.

EDIT - but I'm not talking about things like alternator bearings that get hot, lose their grease, do wear out, and are worth replacing based on mileage if the alternator is already apart. Similar with pulleys - once they lose their grease ...

[ahlem]

Currently around these parts e53 3.0 X5 models are hitting the self serve junk yards. The prices on the related components are very reasonable. I would suggest getting yourself an extra set of what you need at less than $500 and that should last you a really long time as designed.

[andrewwynn]

Absolutely correct. I only use a slide hammer to remove parts where I'm already planning to replace the ball joint or bearing affected. Slow force much better.

I think more likely the RACE that gets damaged from the Impact. The ball is far harder and far less surface area. A big bang will press the balls into the race making nice little dents. Once dented it will usually wear pretty quickly.


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[Bmwtvboy]

Andrew, you speak of pump replacement motor , not the unit. It is sold that way? I seem to only find the entire unit with the extension float. What not replace it all? Is it easy to replace just the motor when the unit is out? My wheel bearings are fine, I don't hear any aircraft whine. BUT, my new conundrum is missing coolant. This happens every few months. The other day I check the o.f bottle and it's empty. Fill it, and for the past three days it's fine. I am wondering, can extensive high RPM driving suck a small amount of coolant into combustion chambers given the high mileage(250K)? I can't seem to find any coolant leaking on the ground. During normal driving n high RPM temp range is perfect. I also look n listen under the hood as soon as I stop driving after reaching normal temp. I am confounded by this one. NO codes either.

[andrewwynn]

A slow coolant leak will evaporate before it drips. Add some UV dye to track slow leaks. They are usually from one of the dozen or so o-rings.

Wife's X is leaking coolant slowly I need to add a pint every couple weeks.

I recently found a drip hanging from one of the hoses on the bottom of the coolant reservoir tank.


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[andrewwynn]

You can buy just the pump. I think I bought mine on Amazon. I couldn't find pierburg so I bought a Bosch. They said it's a new design. With improvements for reliability.

The oe pump lasted about 130,000 miles works out to about 26 mph average with 5000 hours which is very reasonable napkin math.

The pump usually comes with the hose clamps needed and I think the connections for power are push on.

[andrewwynn]

Long drive means fully pressurized coolant system for long periods. This means any minor leak will be doing it's job and with engine hot and lots of wind the leak is more likely to evaporate