1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Shopping List for Front Brakes on GSL-SE

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Old Apr 3, 2011 | 12:26 PM
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Shopping List for Front Brakes on GSL-SE

85 gsl-se stock.

One of my front calipers stuck. Working on a shopping list.

I've already got the pads and I've ordered re-manufactured calipers for both sides.

My disc on one side is gouged and in addition they're both fairly pitted so I think I'll replace them both instead of having them turned.

I also need new hardware as the clips that held the pads in are trashed.

Do I need new front wheel bearings? If so which ones? Looks like there's an outer and an inner.

Thanks.
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Old Apr 3, 2011 | 01:24 PM
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From: https://www2.mazda.com/en/100th/
Originally Posted by comet909
85 gsl-se stock.

One of my front calipers stuck. Working on a shopping list.

I've already got the pads and I've ordered re-manufactured calipers for both sides.

My disc on one side is gouged and in addition they're both fairly pitted so I think I'll replace them both instead of having them turned.

I also need new hardware as the clips that held the pads in are trashed.

Do I need new front wheel bearings? If so which ones? Looks like there's an outer and an inner.

Thanks.
you don't actually NEED the bearings, but if you change rotors you will have to hammer the bearing races out of the old rotors and into the new ones, so its not a bad idea. you need 2 inners and 2 outers to do both sides.

you will need the wheel seals either way.

and some wheel bearing grease, i like the redline stuff, but its up to you
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Old Apr 4, 2011 | 04:20 PM
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As the poster above states, you don't *need* new wheel bearings, but if something goes wrong while you're punching the old bearings out of the old brake rotors, you're going to be hunting for new bearings and races... Not fun on a weekend if you need to drive the car to work the next day.

My recommendation would be to get new bearings, inner and outter (x2), which come with the races, and then install the bearings in your new brake rotors. This way, you'll have taken care of most of the work when the brake system was apart, and you won't have to worry about those parts for a long time. For the cost of the time to do the job, the cost of the parts is minimal. To place the new bearing races, you'll want to get a brass rod, as heavy as you can find it, and a dead-blow hammer. The races are installed by sliding them down into the Brake Rotor and then tapping them into final position against a hard surface like the concrete floor of your garage. You'll know when they're fully seated because instead of a 'tap' sound, you'll get a 'twang' as the Brake Rotor resonates against the concrete. Press the races in from both sides, and then get your favorite wheel bearing grease and use the palm of your hand or a quality wheel bearing greaser - you want gobs of grease in and around the rollers, and try to eliminate as much airspace as possible by displacing it with the grease. After you get the Brake Rotors on the upright spindles, then install the Washer, Castle Nut, and ***this part is important***, pre-load the bearings.

What this means is that you set the rotation weight of the bearings in their races using torque on the spindle Castle Nut - that's why there's a Cotter Pin there to hold it in place once you've set it. Most people get them snug by hand, Cotter Pin the thing and throw on the grease cap - but as the bearings break in, the tension changes sometimes enough to allow changes in caster and toe-in - which are bad for tire wear and handling. Off of my memory, I think the proper pre-load for the SE's is to attach a wire to an exposed lug, attach the wire to a pound-scale (like a fishing scale), and the rotor should turn at 5-6lbs of force. If it turns before you hit 5-6lbs on the scale, then tighten the Castle Nut just slightly. If it takes more than 5-6lbs before it turns, then loosen the Castle Nut. As you can see, this takes a bit of finesse to get it just right, and in all cases, it's better to tighten it to the next Castle Nut break to install the Cotter Pin vs. looser. Try to get both Pre-Load settings on each side as similar as possible, then... a few months after you've been driving the car (~500 miles?), go and re-check the Pre-Load tension again and adjust them, if necessary. This will ensure best handling, tire wear, and toe-in.

The Brake Caliper Brackets are held onto the upright with 2x14mm bolts, and these are removed from the back-side. As you said in your post, if you get a stuck caliper which scores the rotor, it's usually because whoever did the brakes last time didn't take the time to clean the slider pins and regrease them - use a brass-bristle brush and get them shiny, then use a good quality high-temperature grease meant for slider pins; do this every time you do the brakes, and you'll never have a stuck caliper or gouged rotor (caused by excess pressure on one side vs. the other).

Mazdatrix has the Brake Shim Kits you need to replace the metal shields and these are mostly to cut down on noise. I also like to 'glue' them in place using Permatex Blue Bond which comes in ketchup-like containers and which get tacky and allow you to stick the plates to the brake pads. You want those shims to be shiny smooth, as they float the brake pad against the caliper, helping to cut down on noise.

Lastly, after the calipers are installed, be sure you bleed the brakes completely using new brake fluid and never let the reservoir go dry, or you'll have to start over with bleeding the air out.

I'm one for replacing everything I can get to while I'm in there, so maybe also consider replacing your brake caliper hoses with braided stainless lines, too. If you have it all apart now, the time to take it all apart later to fix something else is time saved. Good luck, and this isn't a hard job to complete if you have all the parts you need and the tools to get it done.
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Old Apr 4, 2011 | 09:57 PM
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From: Cincy, OH
Thanks for all the advice guys. Can't beat this forum. I think rx7club is a big part of what makes owning a seven such a rewarding experience.
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