How To Replace Brakes and Rotors
 

I just replaced my brake pads and rotors. I had a few links to other Forums and magazines but I couldn't find a write up here. I decided to document it so I hope you find it useful if you plan to tackle this job. I've added a "health warning" in the opening paragraph but I found the job reasonably straight forward with one exception. The bolts for the caliper mounting brackets are incredibly difficult to break loose.

For any of you who have done the job, feel free to comment and I'll update the How To:cheers:

Brake Rotor and Brake Pad Replacement

This “How To” has been written using the GM manual as a source and including pictures from my own pad and rotor change. Brakes are safety critical so use it at your own risk. If you are not happy working on the braking system give the job to a professional.

Tools Required:

Ratchet with 15mm socket (for calliper bolts)
18mm wrench for caliper bolt collar (front)
16mm wrench for caliper bolt collar (rear)
Or use an adjustable wrench
13/16” socket for calliper mounting bracket bolts.
Hammer
Screwdriver
Low profile jack

Loctite
Degreaser

Front

Identify the front and rear rotors and direction of rotation. The front rotors have a bevelled edge on the hub ring. The rear rotors have a vertical edge. The slots are closer to the hub at the front and wider at the back in the direction of rotation. This disseminates the heat outwards from the rotors. My rear rotors were marked with RR/RL but there were no markings on the front rotors.

Attachment 48153190
Front Rotor

Attachment 48153179
Rear Rotor

Removal
Raise and support the vehicle.
When you are jacking the vehicle at the front, make sure that the jack or the jack lift pad does not make contact with the front fascia, the air dam or the fenders or you could cause damage. Avoid contact with the engine oil pan (2) and the front suspension leaf spring. Place a block or pad between the jack lift pad and the jacking point and make sure it spans at least 2 suspension cross member ribs (1). I then turned the wheels to give better access to the bolts.
http://img.photobucket.com/albums/v2...20To/Diag1.jpg

Diagram 1.
Once you’ve raised the car, put in a jack stand for safety.
Remove the road wheel.
Remove the brake fluid reservoir cap and make sure the level is about half way between min and max. If not drain a little fluid or you risk an overflow when you compress the calipers later in the procedure.
This is probably what you’ll see. My car has been washed a few times without being driven so the old rotors had a slight film of rust.
Attachment 48153180

When you remove the bolts on the calipers and mountings remember the “righty tighty, lefty loosy rule. Look at the bolt you are removing and make sure you turn the wrench the correct way. Remember the bolts are facing towards you so it may not be intuitive. The bolts will have been fitted using loctite and torque tight so they will probably take significant effort to break them loose, particularly the larger caliper mounting bracket bolts (torqued to 125 Lb/ft)!
Warning: Make sure the car is securely supported on the jacks as you’ll exert a lot of pressure on the bolts. Be careful not to lean heavily against the bodywork or you may damage the fender. You may need a large breaker bar or apply some heat from a blow torch to loosen the bolts.
The caliper bolt fits through the bracket on the caliper into a rotating threaded collar with a rubber boot which is mounted on the caliper bracket (see picture below).
Loosen the two bolts (top and bottom) holding the brake caliper to the caliper mounting bracket.
Remove the top caliper bolt. To do this you need to turn the 15mm bolt while preventing the collar behind the bracket from rotating using the 18mm wrench.
Attachment 48153181

(Caliper assembly viewed from above showing bolts)
Attachment 48153182

Diagram 2. Caliper bolts.

Rotate the caliper clockwise and support the caliper assembly with wire (I threaded the wire through the top mounting hole and passed it around the leaf spring) ensuring that there’s no tension on the hydraulic brake flexible hose. Do not disconnect the hydraulic brake flexible hose or you’ll need to bleed the system later.
Attachment 48153183

Remove the bottom caliper bolt and move the caliper assembly aside keeping the tension off the brake line.
Remove the old brake pads. There’s a small tab on the pad. The book says: “The brake pad wear sensor, mounted on the inboard brake pad, must be positioned so that it is in the trailing position during forward rotation of the brake rotor”. I read that as the top of the inboard pad (point of last contact). The picture from the manual shows it at the bottom of the outside pad. My old pads had it positioned at the top edge of the inside pad so, hopefully, GM got it right during build! I leave it to you to decide where to position it.
Attachment 48153184

(Clip extending from back of pad)
Attachment 48153185

Here’s a comparison between the new and the old (very well worn) OEM pads.
Remove the two larger bolts (upper and lower) from the caliper mounting bracket using a 13/16” socket and a long handled wrench. Lift the bracket clear. These bolts are very tight and it will take a considerable effort to break them loose.
Attachment 48153181

Attachment 48153187

Caliper Mounting Bracket
There are two springs fitted top and bottom of the caliper mounting bracket. Make sure these remain in place. There’s a further spring which you can see in the picture above that fits inside the caliper. It shouldn’t come out but if you remove it make sure you refit it the correct way round as it holds the brake pads in place when reassembled.
Attachment 48153188

Diagram 3. Caliper Mounting Bracket, retaining springs and pads.
Remove the spring washers which hold the rotor in place. You can refit these if you wish but they are not actually needed. The rotors hold in place with the pressure from the wheel lock nuts. They were fitted to hold the rotors in place on the production line.
Attachment 48153189

Remove the brake rotor which should lift off easily.
Clean up the various parts particularly, removing rust or contaminants from the wheel bearing flange and the brake rotor mating surfaces. If you don’t, you risk lateral movement of the brake rotor and brake pulsing.
Reassembly
Use Loctite or similar thread locking fluid on the bolts when you reassemble the calipers. Additionally, GM recommend using new caliper bolts.
Install the new brake rotor over the wheel studs onto the wheel bearing flange.
Attachment 48153190

Refit the brake caliper mounting bracket using some loctite on the nuts. Tighten the front brake caliper mounting bracket bolts to 125 lb ft (175 N•m). Make sure the clips are still in place.

Reinstall the lower bolt into the brake caliper assembly using some loctite on the thread.

Fit the new brake pads. They slot in from either side into the upper and lower guides.
Attachment 48153191

Another reminder; make sure you put the correct pads in the correct location. The old pads had witness marks from the calipers with two circular marks on the inner pad where the pistons had been pressing. If you mix up the two pads this will allow you to identify the correct one and get the clip located correctly.

Use a large C-clamp to compress the brake pistons. Fit the clamp (1) over the body of the brake caliper (3) with the C-clamp ends against the rear of the caliper body and against an old inboard brake pad (2) or a wood block positioned against the caliper pistons. Make sure you don’t make contact with the brake hose or fittings or you may damage them. Gently turn the C clamp to compress the pistons. Take it slowly or you’ll cause an overflow at the cylinder. You’ll need to compress them almost fully to get the caliper back on as the new pads are much thicker than the ones that you removed.
Attachment 48153192

Diagram 4. C Clamp used to compress pistons.

Support the caliper, remove the supporting wire and position the caliper against the mounting bracket. Fit the lower bolt.
Attachment 48153183

Rotate the brake cylinder counter-clockwise easing the pistons over the new pads (this picture shows the old pads but you get the idea).

Fit the upper caliper bolt. Tighten the brake caliper guide pin bolt to 23 lb ft (31 N•m).

If you want to repaint your calipers, now would be a good time.
Attachment 48153194

With the engine off, gradually apply the brake pedal to approximately 2/3 of its travel. Slowly release the brake pedal. Wait 15 seconds, then repeat until the brake pedal is firm.

Check the calipers and mountings for security.

Refit the road wheel.

Lower the vehicle.

Rear Pads and Rotors

When you are jacking the vehicle at the rear, make sure that the jack or the jack lift pad does not make contact with the rear suspension mono leaf spring or you could cause damage. Place a block or pad between the jack lift pad and the jacking point and make sure it spans at least 2 suspension cross member ribs.
Attachment 48153195

Diagram 5 Rear Jacking Point
Once you’ve raised the car, put in a jack stand for safety.
Remove the road wheel.
You’ll notice that the rear discs are different to the front having a right angled bevel.
Attachment 48153196

Rear Rotor
The rear caliper is smaller than the front caliper and is fitted with a single piston
Attachment 48153197

You’ll see that the brake line runs across the area behind the caliper mounting bracket bolts. The caliper will have to be removed before you can get in at the larger bolts or you risk damaging the brake lines.
Loosen the two bolts (top and bottom) holding the brake caliper to the caliper mounting bracket.
Remove the top caliper bolt.
Rotate the caliper clockwise and support the caliper assembly with wire ensuring that there’s no tension on the hydraulic brake flexible hose. Do not disconnect the hydraulic brake flexible hose.
Remove the lower bolt and move the caliper clear.
Attachment 48153198

Follow the same procedure as the front to remove the caliper mounting brackets.
Remove the two clips holding the rotor in place and remove the rotor. Because of the E Brake you may find you need a few taps with a hammer to break it free.
You’ll find a lot of road debris and grease around the E Brake adjusters. Clean this up before reassembly. Parking brake adjustment is not necessary as the parking brake cables can be tensioned automatically by cycling the parking brake lever three times. If you feel the need, you can adjust the parking brake shoe-to-drum clearance by rotating the adjustment nut on the park brake actuator. The specification value is 0.38 mm (0.015 in). GM has a special tool to make this measurement.
Attachment 48153199

Diagram 6.
Refit the new rotor.
Attachment 48153179

Reassembly is the same as the front. The brake pad wear clips are also fitted at the trailing edge of the caliper (point of last contact) but as the unit is on the opposite side of the rotor that is the bottom as you look at it. Seemed counter intuitive to me! In any even, I reassembled it as it had been assembled at the factory.
Attachment 48153201

With the engine off, gradually apply the brake pedal to approximately 2/3 of its travel. Slowly release the brake pedal. Wait 15 seconds, then repeat until the brake pedal is firm.
Replace the brake fluid reservoir cap.
Refit the road wheel.

Lower the vehicle.

Bedding-In the Brakes
It’s important to burnish the new pads and mate them to the new rotors.
As you drive off for the first time, make sure you have brake pressure and that there’s no vibration or binding under braking.
Select a long straight stretch of clear road.
Accelerate to 30 mph. Using moderate to firm pressure, apply the brakes to bring the vehicle to a stop. Do not allow the brakes to lock or overheat.
Repeat this 20 times.
As you’ve replaced the rotors and pads it might be timely to flush and replace the brake fluid once you’ve confirmed there are no problems.
All diagrams © Copyright General Motors Corporation.

Excellent, I just posted in tech section yesterday about doing my brakes for the first time and a little goosy about doing it myself. This writeup helps a bunch, saved to my favorites:thumbs:

Great post and by the looks of your old parts it was time for the replacement partsAttachment 48153178

No kidding Steve. I knew they were shot but hadn't realized they were down to metal. That was the front drivers side and was the worst of the lot. Mind you I was ditching the rotors anyway and I haven't driven the car for a good few weeks.

Thanks,DeeGee-this is a job that's coming up soon for me,(I've had the parts for awhile now)so this came at a very good time.
Great writeup!:thumbs:

Excellent writeup, especially the pictures and diagrams. The mods should make this post a sticky so it is sure to be available to future users.

Excellent information and detail with pictures, really great of you to put the time/effort into doing for all. Thanks :thumbs:

Great write up an pics.

Just a note though. The lockwasher retainers on the wheel studs do not have to be installed. They are only there OEM as an assembly aid at the factory.

I do know of one Vette that had tire balance issues that was tracked down to these retainers.

I may have missed it but be sure your E brake is not engaged before you try to remove the rear rotors.

You may also have to compress the caliper pistons to get them to slide over the new pads. You can use a C-clamp and old caliper pad or a caliper compression tool.

http://i103.photobucket.com/albums/m...n/DSC03203.jpg

This is an excellent write up and I can't tell you how all the repair manuals you find out there are so lacking of the important detail you provided!!! :flag:

You mentioned you were open to suggestions so I hope it is okay to throw in a few small things. I totally apologize upfront if these are in your write up and I am in error because I missed it.

- I suggest placing in the required tools section the breaker bar and blow torch (granted not needed 100% of the time but it is good to have the tools ready). You do refer to these tools in the body of your write up.

- You provided the torque settings for the caliper bracket and caliper bolts. I suggest putting in the require tools section that torque ratchets are required so that the specified torque is applied.

- The method you used to support the brake caliper once removed is totally valid. In my experience with brake jobs, I have found that using bungee cords to support the brake caliper is quick and easy because of the hooks on the bungee cords.

Again, let me emphatically state that this is an excellent write up. It is clear you put forth much effort to throw it together. These comments were not intended in any way to be negatively critical of it but to offer suggested enhancement.

Excellent!!:thumbs: Thanks - this is an upcoming job for me shortly...

I see you installed new rotors, but I have a question about re-using the current rotors.
I reacll years ago when replacing pads the rule was to have the rotors turned - - I read elsewhere thats not necessary?

Also, if switching pad material say from oem to like a Hawk HPS or HP+ would rotors need to be turned to clear the old material off before bedding the new pad material.

Hope I'm making some sense....

Thanks for the input. I'll add those comments:cheers:

Thanks John

I think I mentioned the point about the spring washers on the rotors.

The E brake is absolutely correct and I'll add that:cheers:

Must admit I've only ever had rotors turned if I had vibration. I fitted the drilled/slotted for aesthetic reasons. The OEM rotors are good IMHO and they clean up quickly in use but others may have more experience.:thumbs:

Brake job
 

Excellent write up.

May I offer two thoughts to the discussion? First, the caliper bolts are fairly easy to break, especially if you are using an air gun (3/8" drive). Ask me how I know this?

So, you should buy at least one or two new bolts before beginning the job. They are not real expensive, about $6.00 each. The problem is most Chevy dealers don't stock them, at least not around here.

Second, when you compress the caliper piston back into its bore you are pushing all the dirty brake fluid back into the line, which can sometimes effect the ABS sensor.

The factory actually suggests that you open the bleed screw when you compress the piston which will cause the fluid to run all over the floor, unless you remembered to put a piece of tubing on the bleeder. Ask me how I know this!

Seriously, if you're going to the trouble to do all of this work, this is the ideal time to flush out the old brake fluid and replace with new. Also a great time to install some braided stainless steel brake lines, which really improve the brake feel.

You can rent a power bleeder from some auto supply stores, or just get your buddy, friend, wife, girl friend, etc. to do the pump-pump-pump-hold deal.

Start at the right rear wheel, then left rear, then right front, then left front.

Ken Edney
Chandler, AZ

Some good points and thanks for the input. Thinking about how the average DIY'er would feel, I decided to draft the "How To" so that the brake lines are not broken. Thats also the way the manual suggests. I made the point at the end, that it would be good to flush and refill the system once you were sure your "DIY" efforts had worked.:thumbs:

When you say the factory suggests you open the bleed screw, where is that stated?

I question this because both my '93 C4 FSM's and my '01 C5 FSM, both state the procedure is to draw the brake fluid down in the reservoir to between the max and min level marks. Then using C clamps compress the cylinders. In fact it suggest when replacing pads and/or rotors there is no need to open the lines.

:iagree:I used the shop manual advice to draft the "How To"

Actually the FSM (Factory Service Manuals) state the opposite. They suggest first mic the current rotors for proper thickness, if at or close to minimum, replace with new rotors. The FSM does provide details for the machinist if they re-surface the rotors. But if just replacing pads and the rotors thickness is good, just put the pads on and following the bedding procedures.

:thumbs: We both do, I've read several of your write-up's before. Same here, when I write a procedure I use the FSM steps and add in my tips I pickup while doing the procedure that is not mentioned.

^^^^^

You do both know that the Techs at the stealerships don't always follow the FSM procedures verbatim.:willy: