OK you rx7 heads! Help!! I am trying to change my front brake pads (and this is the 3rd car i have changed front disc brake pads on) My usual method is to just losen the caliper bolts which bolt it to the hub and stick em in BUT tht is impossiblebecause there is something front the suspension blocking the lower bolt and not allowing a wrench to get in.

SOOOOOOOO i did what I shoud of in the first place and got a haines, ok here is my problem with the haynes method
Step #1 remove wheel: OK!
Step #2 remove 4 pins holding 2 locking plates to the caliper...........I CANT FIND THE PINS!! I swear the pic in the haynes must be a different caliper or something becuase there are NO pins at all (or i am totally missing them) to remove! Help!! Anyone have any idea what im talking about? It makes it look real easy in the haynes repair manual there are 4 small pins somewhere that hold these 2 plates in and then the caliper just slides off and the pads then can be changed? I cant find the pins or see where these plates are going to come from.

PS: YES i have the right haynes repair manual and it says the front are all the same except in 81-85 there was a rear disc brake option (which i dont have and which doesnt matter cuz im working on the front.

 

I find the Haynes repair manual a joke. Hopefully someone here can help ya out.

 

Are you only changing the pads? If so, then there's no need to go anywhere near that bolt on the bottom of the caliper mounting bracket (the one that the wrench won't fit onto because of interferance from the steering knuckle). That bolt, and the upper one for the same bracket, only needs to come out if you're removing the brake rotors for re-surfacing or replacement. For that job (when it becomes necessary) you'll need a 14mm off-set box-end wrench with part of the top surface of the business end of the wrench ground away so that it will fit onto the bolt without slipping off when pressure is applied.
To change the brake pads, remove the lower bolt on the brake CALIPER, the one that's 17mm. It may also be necessary to LOOSEN, but not remove, the top 17mm caliper bolt. Then pull the bottom of the caliper back toward the rear of the car (it will pivot on the upper bolt, which is still installed) until it clears the rotor. The old pads, spring, and shims can then be pulled out and replaced by hand.
Install new pads in reverse order from this process, making sure to put springs and shims back into proper position. There's debate over the effectiveness of applying "brake-quiet goop" (the blue or red stuff) but go with whatever you're comfortable with. I've found that stuff to be a waste of time and money, but that's just me.
But before swinging the caliper back down over the new pads you'll need to use a C-clamp to push the piston back into the caliper in order for the new (thicker) pads to fit. If you've changed pads before on other cars you'll already be familiar with this step.

 

With the following exceptions. Only remove the lower caliper bolt, it has a 14mm head IIRC, not 17mm. Once thats removed, the caliper can be rotated up out of place. There is no top bolt, just a slider pin as I recall.

 

I looked at the procedure in the Haynes and then attempted to change the pads on my '84... Well the Haynes only shows the earlier style caliper mounts.. Not even a mention of the newer syle in the "supplement" chapter. Time to invest in a factory service manual...

Ben

 

I think you're right about the upper slider (I must have been thinking of the wife's Nissan), but I'm pretty sure the lower caliper bolt is 17mm on the 1st gens.

 

There should have been a Hayne manuals for 79-81 / 82,83 / 84,85 / 84,85 -SE

While they are all first gen cars, there are way too many differences between them to fit them in all in one book.

 

Glad I read this thread - I was also pulling my hair out with the Haynes manual for the front brakes on my 84 GSL-SE. I thought I was doing something wrong but now I know it was right! From now on, go with the gut!

Two additional questions:

1) the pads I took off did have shims but I did not see a spring (the "z" shaped wire that came with the brake hardware package. Do you need this and where does it go?

2) Just curious, do the brake pads just rest in the caliper or is there supposed to be something that pushes them back once they are done doing their job? Make sense?

thanks for the help!

 

That damn bolt on the bottom that you have to unbolt part of the steering knuckle to get too....... what a pain in the ***. Worst design ever. Sorry, just had to rant a bit.

 

Throw your Haynes manuals away! They try to describe how it works for too many different vehicles and get it wrong for every one of them.

For the money, clarity, and time saved - you'll never go wrong with a Mazda FSM, even at $80 which I paid for mine. They are specific to your year, cover your car, ONLY, and also have tips and tricks that you can't get from the 'generic' manuals.

On the brakes themselves, there is the single 14mm pin bolt at the bottom which lets you rotate the caliper up and out of the pad mounting braket. Once the caliper is up, changing pads is really easy. The brake pad hardware consists of the metal side shims (top and bottom clips to hold the pads), the pad shims (flat metal pads which allow the pad to shift under the caliper arm and piston), and the 'Z'-springs.

If you notice, on your replacement pads there are holes drilled in the outboard edge. The downward tip of the 'Z'-spring goes into this hole on the OUTSIDE pad, then the other 'end' of the spring goes above the caliper piston dust seal - it just sits against the inside edge of the caliper, just above the seal. This helps to push the outside pad away from the disk when you release the brakes.

Also, your brake rotors have a slight amount of 'runout' to them that pushes the pads away from the friction surface. This occurs as the disk is just slightly out of true, and as that 'bump' hits the pad, it knocks the pad back just far enough that it's not gliding on the rotor surface generating heat and burning off pad material. This runout also helps to center the caliper and works effectively on both pads. The downside is that when you apply the brakes you have to apply a little more pedal pressure at first (soft pedal) to let the hydraulic fluid fill the cylinder bore and force the pads back into contact with the rotor - a small price to pay for long-wearing brake pads, though.

The FSM says runout is okay. Race cars on the track that need instantaneous braking and immediate pedal force have zero runout on their brake rotors - and these get changed every few races, anyway. Brakes run hot, but most racing compounds need to be hot to function well, anyway.

Little tidbit of knowledge for the day,

 

Thats only if you need to remove the mount to change the rotor and/or bearings. Not for a simple brake job.