Under the Hood: Converted van pulls to the left

McClatchy-Tribune Information Services

November 13, 2017

Q: Please see if you can shed some light on my problem, which the local Ford dealer cannot solve. It’s a 2002 Ford van that was converted into a Pleasure Way mini motor home when new. We’ve had lots of problems with it pulling hard to left when braking but drove straight. We’ve put lots of work and money into the front end and brakes, now no pulling when braking but it still drifts badly left when driving. The tie rod ends and sleeves have been replaced and a camber-caster kit installed, and it’s been aligned twice.

The vehicle still drifts to the left as badly as ever. The dealer said that since the generator and propane tank were on the driver’s side, perhaps that is why the drifting. I can't believe every Class B motorhome on the road, most of which are set up like mine all drift left. Can you offer any suggestions?

–– Ron Drozd.

A: When diagnosing a pull-to-one-side situation, I’d start by swapping the front tires side to side, along with a fresh set of eyes checking suspension and steering parts for looseness or damage. Sometimes a tire can have an off-center belt that contributes to pulling. The addition of the caster-camber kit (ball joint stud adjuster-bushings with an eccentric center hole) was a great move, as this allows fine tuning of front alignment angles.

Most vehicles track best with about a half degree more positive caster on the right side suspension than the left. Caster is the angle of the upper and lower ball joint center-lines, similar to the angle of rake of a bicycle’s front fork. The extra half degree on the right helps the vehicle track straight on a crowned road, rather than pulling slightly to the right. Your van may have a larger caster spread than this, possibly due to an alignment tech calling it "good" when the caster is at an unfortunate spread within the one-degree allowable tolerance. Loosening the pinch bolt and rotating the adjuster bushings to the desired rotational position, getting both camber and caster just right, is a lot of work, and can be frustrating. It’s also possible a suspension part is tweaked slightly, and the ideal caster spread can’t be achieved.

After viewing images of identical and similar Class B mini-motorhomes (a large and heavily loaded van) and looking at how close they run to the maximum gross vehicle weight, I think stability could be noticeably enhanced by adding either an air bag or elastomer rear suspension kit. Firming up and leveling the rear suspension could do a lot of good minimizing the effects of generator and propane tank weight, keeping the front suspension pointed straight.

Q: My 2003 BMW 325ci convertible has about 98,000 miles. I had a coolant leak I fixed a few months back; had to replace the plastic reservoir as it is notorious to leak at seams. Since that time, whenever I start the car (being parked for 8 hours or so) the coolant light stays on for a minute and then goes out. Coolant has been always full. Last week I noticed that if car is parked on a (downward) slope the light doesn’t come on at all.

–– Gary P.

A: It seems your expansion tank float switch is indicating low fluid level as the cold fluid level contracts. With the engine cold and unpressurized, remove the expansion tank cap. With the proper fluid level, the tip of the float (a slender red rod) should be between flush with the top of the tank cap threads and protruding 0.8 inches above this. You may be a bit conservative with the fluid level?