Are my clutch problems related to a bad emergency brake?

Question: I have a 2006 Nissan Frontier with a V-6 engine and 110,000 kilometres on its odometer. We use it as our second vehicle, mostly for driving around town.

The clutch, a replacement installed by my dealer less than 25,000 km ago, already needs to be replaced, and I’m wondering why. Could it be because I park every day on my steeply graded driveway and keep the truck in place with a bad emergency brake?

C.N. Answer: I can’t imagine the clutch slipping as the truck backed down the driveway. The clutch’s pressure plate has more than enough pressure and engagement with the clutch disc and flywheel to handle and hold the engine’s torque as you accelerate, so I really don’t believe it would slip under the pressure and weight of the vehicle parked on a slope.

You didn’t mention the clutch symptoms you are now experiencing. If the clutch is now slipping under normal acceleration, the problem is probably wear on the disc engagement surfaces. If the clutch now shudders as you engage it, the issue is probably damaged or broken pressure plate springs or a broken buffer spring in the clutch disc hub. I’d want to see the clutch components when they are replaced to determine what caused the problem — wear, a broken pressureplate spring, damaged disc or something else.

Q: I have a 2006 GMC Envoy Denali with 301,000 kilometres on the 5.3-litre engine. In the past six months, the low-oil-pressure light comes on at a cold start or even after the truck has been sitting a while. Once pressure goes up, the light goes off. A GM dealer said that they have not seen a case of a bad oil pump, so they suggested I replace the oil-pressure switch on the back of the engine. I did this but the problem still is there. Any ideas?

R.G. A: That’s a lot of miles, for sure. Do you hear any engine noise or clatter on a cold start? Usually, if there’s low oil pressure or poor oil flow at startup, you’ll hear valve clatter or possibly a dull knock from engine bearings.

It’s a bit unusual for oil pressure to be low on a cold start, since its viscosity is at its highest when cold. But poor oil flow at startup would lead to low-oil-pressure symptoms. My first thought is that oil sludge is restricting oil flow through the oil pump screen at startup, delaying the buildup of oil pressure. My second thought is a leak between the oil pickup tube and the oil pump body, bleeding off oil pressure.

Check that the correct oil filter is fitted to the engine. Also, there is an oil pressure relief or bypass valve in the oil filter adapter. The wrong filter or a damaged or missing bypass valve could create these symptoms.

Q: I’m considering adding a trailer hitch to my 2011 Honda CR-V so I can haul my mobility scooter around on a platform. How difficult is it to do this? What kind do I need?

N.M. A: This is reasonably easy to accomplish.

There are many choices available for a bolt-on receiver, which is a type of hitch that allows accessories such as a platform, step or bike rack to be plugged in and pinned in place.

Receivers are classified by their weight capacity. Class 1 and 2 receivers have a 1.25-inch square socket and are for light loads such as small trailers, light duty platforms and bike racks. Maximum tongue weight (downforce) with these is roughly 90 to 135 kilograms, and maximum trailer weight is 900-1,500 kg. These light-duty receivers fit more snugly under the back bumper than the larger receivers I’ll describe next.

Class 3, 4 and 5 receivers all have a sturdier, less attractive structure, a two-inch square socket, and can tow up to 2,200, 4,400, and 7,700 kg respectively (typically with the use of much larger vehicles).

I researched ramp-type scooter platforms and found that virtually all require the use of a two-inch, Class 3 receiver, due to tongue weight and twisting load considerations. This bulkier receivers can carry tongue weight as high as 300 kg and trailer weight up to 2,000 kg (far beyond the CR-V’s 680-kg towing capacity). Looking at scooters and platform weight, it seems you’d want to have a receiver rated at 160 kg or higher tongue weight. In order to bolt on the receiver, the exhaust system must be temporarily lowered, and the rear underbody panel must be either trimmed or removed. This a job for a pro or an accomplished do-it-yourselfer, requiring about an hour of time. If you drive in places with abrupt angle changes (driveways, for example), there’s a chance of bottoming out the receiver or ramp on the ground. So, choose a receiver that hugs the CR-V body as closely as possible.

Q: My brake-warning light came on the other day. How serious is this? Can I drive carefully until my day off to take it in, or do I have it towed as soon as possible?

C.H. A: Are you referring to the amber-coloured anti-lock-braking system light, or the red-coloured brake warning light? If it’s the amber light, you’re OK to drive for a few days or more before having it checked out. Your brakes will work normally but there won’t be any anti-lock assistance, should you need it. The red light is another story. It could be triggered by a number of issues, depending on the vehicle make, and some are quite serious.

Among the possibilities: a faulty parking brake switch or circuit, low brake fluid level, hydraulic imbalance, electronically controlled braking system fault, and worn brake pads.

Check your brake master cylinder fluid level. If low, add the appropriate DOT 3 or 4 brake fluid (check label or listings to be sure of which to use).

Also check to be sure your parking brake handle or pedal is returning fully to the unapplied position. If neither of these fix the light, you need to take this seriously and get it checked right away. If the brake pedal feels normal, and the car stops as it should, I’d drive it to the shop. If anything doesn’t feel right, be sure to have it towed. Paul Brand, author of How to Repair Your Car, is an automotive troubleshooter, driving instructor and former race-car driver. Readers may write to him at: Star Tribune, 425 Portland Ave. S., Minneapolis, Minn., 55488 or via email at paulbrand@startribune.com. Please explain the problem in detail and include a daytime phone number. Because of the volume of mail, he cannot provide personal replies.