Don’t Make My Mistakes Working On Your Brakes

I screwed up one of the easiest car repair jobs in the book. But you can avoid my pain easily with these tips.

byAndrew P. CollinsJun 7, 2022 8:00 AM
Don’t Make My Mistakes Working On Your Brakes
Andrew P. Collins
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Replacing brake calipers, pads, and rotors is a straightforward task on most cars. If you’re even slightly competent and confident with tools, this is generally a task you can take on yourself. That said, there are a few tips you won’t find in the service manual that will really help you have an easier time.

This isn’t a step-by-step tutorial on brake repairs. It’s a supplement to help you avoid misinterpreting your car-specific instructions or simply making an easy mistake like overtightening a hose and adding an extra step to your project. I would know, I did exactly that. That leads us right into my first tip.

How To Have Better Luck With Your Brake Job

Be careful when twisting brake hoses and don’t overtighten.

Securing a brake hose to a brake caliper is a royal pain because you basically need to spin the caliper (big, heavy) while holding the hose still (rusty, wiggly). If you bolt the caliper into place first, you won’t be able to tighten the hose without twisting the hell out of it, which you don't want to do, because a twisted hose can snap.

The tip of the hose will be threaded, and it feeds into a threaded slot in the caliper. The annoying part there is that, as I discovered, it’s really easy to overtighten, and overtightening can break the threads. Once the threads are broken, the caliper or hose could be toast. In my case, I ugga-dugga'd the hose down so hard that it straight-up eviscerated its own threads. No threads meant no seal, and my brake system proceeded to pee out fluid at an alarming rate.

"Welp, there's your problem." The hose on the left is a new one, the hose on the right looked the same until I tightened it so aggressively that the threads got worn down to nothing. I'm not even strong—be careful with brake parts!

So I have a couple of practical tips here: Just tighten the hose until it’s snug, and don’t go gorilla on it, even if there are still threads exposed between the caliper and the hose. In many cases, the hose threads are simply longer than the insert in the caliper. Just take your time checking for leaks by wrapping a dry shop towel around where the hose mates to the caliper.

I knew all this and didn’t even think I was wrenching it down all that hard, but I still managed to screw this up. Ultimately, I think the caliper was still usable and only the hose needed replacing, but I didn't feel like trusting the caliper threads anymore so in went a new one (along with, obviously, a brand-new hose). Luckily for me, these calipers were cheap so the only real penalty was downtime. But they can be very expensive parts—especially on higher-end cars, and especially on the front.

On a related note, make sure the final resting position of the brake hose is straight and smooth. If it gets all twisted up, that can mess with your fluid flow or fatigue the hose and make it rip.

Treat brake fluid with respect.

A brake hose clamping tool (sometimes called "pinch-off pliers") like this is good because it's softer than a metal Vise Grip or channel lock tool, and therefore less likely to damage the hose it's biting.

Brake fluid is extremely caustic (eats paint, bad for skin, not great to breathe) and hygroscopic (meaning it likes to absorb water, which ruins it). Take care when you remove a caliper or crack open a hose—you don’t want that stuff spilling any more than necessary. Consider a clamping tool to keep fluid from flowing, and/or stick an open end in a plastic bag. Don't leave your brake system open, at all, any longer than necessary.

Here's a great example of just how ferocious brake fluid is—the circle around that hose mounting inlet was coated with the same grey paint you see on the rest of this caliper. Then I screwed up the threads on the hose and caused a fluid leak—I had to leave it for a day, and the brake fluid completely ate the coating at the mating point.

Make sure you keep an eye on the fluid level in the reservoir, too. It’ll drop more than you might expect as brake fluid leaks out during a caliper change.

Don't lose track of your brake pad shims.

Brake pads will have little metal or rubberized backing plates (shims) designed to keep them from rattling around. If you bought good new pads, they probably came with new shims pre-installed. Still, you'll want to double-check, and if they aren’t included, grab the old ones off your current pads or see if you can order a new set at your local parts store.

Take care not to lose the little anti-rattle clips.

Another small but important piece of hardware in disc brakes is the clip, or rather pair of clips, that cling to the top and bottom of your brake pads. They’re easy to lose track of, so don’t throw out your old ones until you’re sure you know where the new ones are.

Grease all the parts that need greasing.

Slide pins, mounting clips, and the back of pads sometimes require special brake part grease. If the box of parts you bought says anything about greasing, make sure you lube them up or they’ll sound terrible and wear out faster than they should. Your brake kit may very well come with grease, but if it doesn’t, it’s readily available at auto parts stores. You’ll only need a little bit for one car’s brakes, so go ahead and get the tiny tube unless you’re planning on doing a whole bunch of brake jobs.

Handle greased parts carefully—keep grease off the rotors and inside of the pads.

Once you’ve greased what needs to be lubricated, take care not to get that slippery stuff onto the surface of the brake rotor or the side of the pad that it comes in contact with. It’s not that easy, especially as you’re juggling that unwieldy caliper. Take it slow, because contaminated brake parts could result in a reduction in performance.

Take your time and install bolts in the right order.

My brake job was on a Mitsubishi Montero, and one of the quirks of its rear brake caliper installation process is that you need to install an upper bolt before attaching the hose. This requires a wrench to tighten it because there's no room for a ratchet. Your car might have a similar situation. Take your time and use your puzzle-making skills to work the assembly order out if it’s not crystal clear in the instructions.

Amazingly, I manged to screw this up twice in a row—I threaded the hose on only to realize I'd forgotten to slide that upper bolt in first. Then I did it again on the other side! I really need to take my own advice and slow down, huh?

Don’t bend any shield pieces (and inspect them when you’re done).

It might be tempting to bend one of the thin metal shields you'll find near the brakes away while you’re working, but doing that can weaken them or force them to contact the brake, which you definitely don’t want. Those little shields are not particularly robust, so be careful not to mess with them.

Bleed the brakes afterward, being careful with the bleeder screw.

You don’t need to bleed the brakes if you didn’t remove the fluid hoses that connect to the caliper, but if you did, you do. Any little air bubble is no bueno in your braking system, as it causes inconsistent performance. Plus, air is usually moist and moisure in your brake lines leads to rust where you really don't want it. So make sure you use your bleeding method of choice after any job that involves removing brake hoses.

Pump the brakes back up after turning the car on.

When you’re ready for a test ride, give the brake pedal some boots to rebuild pressure in the braking system. Otherwise, you might try to stop in traffic and be surprised by lag time on response.

Final Thoughts.

Hope that insight helps as you get your tools and YouTube videos lined up for your next brake job. You’ll definitely want to search for instructions for your specific car to see if there are any unique quirks to deal with, but generally, disc brake servicing is a job that can be done by anyone willing to get their hands dirty and turn some tools. Good luck, and don’t forget to add any more idiot-proofing ideas for brake jobs in the comments. Meanwhile, I'm happy to report that my Montero is stopping just fine after replacing that toasted brake hose with a fresh one.