So here goes, recently got my car back and was at a mates place last night working on some electrics. On the way home on the highway i hear a knocking sounds in the front of the car (like a socket or something has fallen off or the car has run over a piece of metal and flicked it up). Wasn't that loud but I could hear it. Thought i possible could have left a socket or something in the bay and it had fallen out. Anyway so i keep going but im now a bit worried and as i slow down to turn onto the freeway i hear a much louder knock, something definitely fell out this time. Pulled over (didnt have any light with me and its 1:30am), originally thought it might have been suspension so was checking all the bolts on the suspension and nothing seemed to be missing or anything. So now im crapping myself that the wheel is going to fall off or something (checked the wheel nuts first ) so i babied it home, ~ 30km doing 80 on the freeway. Freeway was pretty empty so i didn't use any brakes all the way but when i was exiting i had to slow down for the lights and when i went to brake the pedal went right to the floor and i could hear a slight grinding noise. Previously there was a slight roughing/grinding noise but I thought that may have just been the pads or the disc as the cars been sitting dormant for almost 4 months. I was pretty close to home so i just used the handbrake but when i got home i looked in the wheel arch and the caliper has moved 90 degrees from its normal spot and is on the piss. Grinding noise was it touching the inside of the rim.

Looked at it this morning and took the wheel off, caliper has rammed onto the dust shield but with a bit of wiggling came off, pads arent grabbing anything which explains the loss of braking and the two big bolts holding the caliper on are gone (i'm guessing those are the things falling out of the front of the car i heard). So now im like WTF.

The brakes haven't been touched, workshop hasn't touched them but they checked them and they weren't loose when i got the car back a week ago, i haven't touched the brakes and i've prolly done about 200-300 kms since i got the car back, and i have done some reasonable heavy braking when i give it a bit of a fang but apart from the very slight grinding noise i have heard nothing.

So anyone got any ideas on what happened and how to fix it so i can drive it to the workshop? My mechanic mentioned that the bolts should have a spring washer with them and are usually loctited in but this is a new rolling shell i bought so this was the first 200-300 km i have done on the car. Also the bolts haven't sheared off as theres nothing left hanging in the thread.

One pad has a deep groove in it as its been on the disc on an angle, however i cant seem to fit the caliper back over the disc, the pads need to be pushed out more, how can i do this?

Pics:

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Lastly, does anyone know the bolt i am talking about and the sizes and stuff? I know its got a 17mm washer head but i can't remove the other side bolts (their tight as hell) and i dont think its a good idea for me to remove them.

Kinda hard to tell, but it looks likt one of the bolts on the back is missing?

Sounds like the bolt was just loose and fell out. The only reason you can't slide the caliper over the rotor is because you have pushed the pads out too far when you attempted to use the brakes. They will need to be pushed back in.... I am not 100% sure, but I think you need to screw the piston back in on the RX7's. Your pads are more than likely OK to reuse, but it might be worth rubbing out the groove with some course sand paper laid over a flat surface. Check the bolts are secure on the other calipers too. Sounds like the previous owner might have slapped some parts back on without much care

Those bolts dont just fall out. If it was a rolling shell someone probably fucked around with brakes then just didnt put them back together properly. Like Rotang said check the rest of the brakes before driving again. If your pad has a big groove in it then you will need a new set of front brake pads. If the discs are within measurement get them machined as well. Put a hose/container on bleed nipple and crack that open to make it easier to push pads back into caliper.

yeah both bolts are missing and any work done did not involve the calipers or even the brakes. I just learned that the bolts should be loctited in and should contain a spring washer. As for the pads they are screwed. Inside pad has the bottom half eaten away as it was rubbing on the edge of the rotor on an angle. I just got to try get the pistons to get back in so i can fit it over the disc.

As for the rolling shell the guy i bought it off was driving it around and everything, except when i mentioned i didn't want the engine he just removed it.



Doesn't that mean i need to rebleed the brakes? Is there any other way you can force the pads apart?

if he checked them and he said they were fine take it back and make him fix it cos there responsible and they should be fixing it not you
make them pay for the tow truck and make them deal with it

but if i was you i think i would be taking my car somewhere else after something like that

i think i may have phrased that badly. They helped me out heaps with the car but the work done did not require the calipers to be removed or have anything to do with the brakes however there was nothing obviously wrong that they saw when working under the car (ie. if the bolt was clearly loose or dodgy they would have seen to it but there was nothing wrong). I don't expect them to check that every single bolt and screw in the whole car is tight when im only getting work on certain sections done.

Anyway thats going away from the point, just wanted some opinions on what people thought, and how to fix it. Cheers for the input tho

Just suck some fluid out of the reservoir and leave the cap off, then use the old pad or abit of wood with a g-clamp to get the piston back. Thats for the front only, rears have to be wound in.

he is right, just push them back in enough to get the caliper back on. Or u could use a big pair of multi-grips. Then simply remove one of the bolts from the LH caliper to use as a match and take it to bunnings or something to match something up.

There is no way in he'll these bolts "come loose by themselves" usually torqued up pretty tight to stop things like this happening. Someones definately fucked with those bolts that's got NFI.

When reassembled use new spring washers and a loctite!!!!!!! And use high tensile bolts

These bolts can come loose with regular driving, I had it happen years ago on mine and my parents had it happen recently on their subaru outback.

They are generally something that only gets checked when the calliper is removed for any reason.

There is no reason these would come loose on their own, only reason would be the thread has been stripped out or they were left loose. Just do as advised and you should be right, if the thread is stripped, then your gunna have more issues.

then u will need a new stub axle if thats the case

viewtopic.php?f=4&t=170863&start=0
cough

bolt left loose.

u do not need spring washers under them unless they are factory ones,they were simply loose .

That was my master cylinder and booster which has since been replaced.

Do i need any washers at all? I checked the thread and they seem to fine inside. If i dont need washers i plan to get a hi-tensile stainless bolt that fits in there and putting some vibration loctite on it an using a rattle gun to put it on. Does that sound like a good idea or is there a better method?

spring washers won't hurt tho!!! I'd be doing it, especially after that happened

also better of torquing the bolts as per manufactuers specifications! Not with a rattle gun lol

pm'ed ya man

spring washers wont save shit,i work as dealer tech and i can tell u very few have spring washers,most have simple flat washers.also spring washers only work wel in low temp environment,if u heat them up heaps (eg very hi brake temps) they lose their spring anyway,hence why spring washers arent typically used on exhaust bolts and nuts.u can egt the multi-washer assembly type and they work better in that situation.

all in all,a tight bolt wont come loose.

I wouldn't be that quick to jump on the stainless bolts. SS expands more than ordinary steel so it may lose clamping force when hot.

The std bolt is 10 grade and has a spring washer a flat washer to stop the spring washer galling the Alum

Front caliper 58-72 ft-lb

Mazda used SS spring washers on the exhaust and they stay springy

everyone has their opinions mate but when it all comes down to it -just fit the correct bolts mazda specifies and torque them to the correct specifications

= no more problems

= problem solved