A worn bushing can allow the control arm to shift position, changing alignment on braking, resulting in pull. The brakes may be fine.

Despite all the sophistication of modern vehicle braking systems, the majority of customer complaints still involve pedal feel, pulls, noise and friction-material wear. Though at times the blame for these conditions may lie with the fancy stuff, you'll invariably save time by starting your investigation by assessing the basics – not just in the brake components themselves, but in related systems, too.

Which is it?

Worn suspension components like a bushing and strut and tired-out front-end items like this idler arm can cause pulls upon brake application.

Here's "Troubleshooting 101" rule No. 1: look up TSBs. In this case, Ford bulletin 94-5-5 says it's not too hard to tell the causes apart. Start by disconnecting the return hose at the bottom of the brake-fluid reservoir; plug the reservoir port and keep the hose above the HCU to minimize spillage. Then, get ready to catch fluid that may come from the line as an assistant begins depressing the brake pedal while you watch the hose.

Sometimes a defective non-brake component has obvious damage that you can see while inspecting the brakes, like this damaged CV boot. Excessive CV joint wear may lead to noise during braking — a condition that won't be fixed by a friction replacement.

Monitoring Tire Pressures

An early lesson in "Brakes 101" is that deceleration pulls aren't always caused by brake problems. Suspension abnormalities like a weak spring or shock, worn ball joint, tie-rod end or bushing, or internal tire problems/uneven inflation are all potential causes of pull. Sticking with tires, if inflation is even, sometimes swapping tires side-for-side makes the pull swap directions or disappear entirely, indicating a tire problem.

Federal regulations have required that all cars and light trucks (without dual rear wheels) be equipped with tire pressure monitoring systems (TPMS) since August 2007. You might think one part of troubleshooting pull has been simplified. If the vehicle has TPMS and there's no dashboard indicator warning of uneven tire pressures, they must be OK, right?

Not necessarily. Bill VandeWater, director of consumer products and technologies at Bridgestone Firestone North American Tire, says there are some very good reasons you don't want to scrap your tire pressure gauge and start relying on a vehicle's TPMS. And not just for brake troubleshooting.

VandeWater says two problems make TPMS unreliable as a troubleshooting tool: warm-up period and degree of accuracy.

Regarding accuracy, he points out that the federal rules only require that monitoring systems warn the driver if any tire's pressure drops 25 percent below spec. In some cases, a pressure loss may be enough to induce a pull but not enough to light the system's warning light. As for the warm-up period, because inflation readings change as a tire heats up, TPMS isn't required to report on pressure readings for the first 20 minutes after the vehicle is started. If the customer lives near your shop, the system may not even be up and running when you're evaluating their car or truck.