scheistermeister

if you replace all 4 calipers and in the process let the MC go dry do you have to bleed the MC too?

reason being is im using a vacuum pump and ive been bleeding the rear caliper forever and fluid still has a lot of bubbles with it coming threw the tube to the pumps resivuor.

VietFC

yes, you have to bleed your brake lines.

cwsttu

make sure you bleed both bleed valves on the rear brakes.. otherwise they will not lose that mushy feeling and it will be hard to stop

Turbonut

iTrader: (1)

Takes time with a small vacuum pump. Get a piece of hose and slide it over the bleeder. Immerse the other end in, I use used, brake fluid. Have someone pump the brakes, hold pressure, open bleeder and let fluid into container. You can see if bubbles are present each time. Actually I've even bled the calipers by myself. Just leave the bleeder open and as you pump out fluid, no air will enter as the hose is in fluid, and no fluid will come back up the hose. KEEP master cylinder filled, or you'll need to start over.
As above, there are 2 bleeders on each of the rear calipers. Bleed bottom then top.

Icemark

Remember to bleed the furthest line (pass rear) first and work your way to the nearest line to the brake MC.

Syonyk

Hm... I should bleed my lower rear screws. Haven't pulled the pistons off or drained them, but... couldn't hurt. I've bled everything else.

One thing I've found really, really useful is a "one man brake bleeder kit." It's a little bottle with a hose on it, and fills with brake fluid, but will suck fluid back in instead of air (the hose drains into the catch container, and sucks existing fluid... I'm doing a ****-poor job of describing it, but it works). I've bled my entire brake system by myself without problems. Made a small mess in the driveway, but that's a given (and makes the house look "lived in" - clean driveways look fake).

-=Russ=-

patman

iTrader: (3)

number one brake mod of all time is 'speed bleeders' located at you local harware store.. cost is like 15 bucks for all 4 wheels, they are bleeder screws with a check valve in them; you just open it, pump the pedal a few times, and close it...works like a charm.

here is a trick that maybe i shouldn't tell you, but i have used it many times (i work in a garage summers, aside from my own cars, and have seen some major bitches when it comes to brake systems)

get an old fuel pump/washer pump or similar and fit a 3/16 inch vac hose to its outlet. put the inlet in a can of brake fluid. make sure everything is very CLEAN. take the cap off the master cylinder, put the hose on the bleeder valve, and run the pump off a spare battery or a battery charger. let it pump about a cup of fluid through. this will make a BIG mess in your engine bay, but is guaranteed to fill the caliper and line with fluid and push out 99% of the air. repeat for all four wheels, then all you have to do is bleed each wheel the normal way real quick and you have near-perfect brakes.

pat

tecknomage

intresting know i have some understanding of how to bleed brakes

Smoken'

iTrader: (1)

Just remember that brake fluid takes off the paint...

scheistermeister

well after bleeding the living **** out of the brake lines it still didnt feel right to me. so i had someone else who works on a lot of cars drive it and they thought it was fine.

it does stop and can stop hard, its just not what i was expecting. but then again the car im comparing it to is a 87 porsche 924S, but it only has single pistons up front with rubber lines and some generic pads. i would think with new fluid 4 pot calipers corksport ss lines and KVR pads that the rx7 would bite at least similar if not way better.

i mean when i ever so slightly even touch the pedal on the 924S it stops hard and its really easy to lock up the wheels. on the rx7 its pretty hard to lock up the wheels, but possible. and it doesnt start to bite until the pedal has gone about half way to the floor and bites hard right before the floor.

would this be corrected by adjusting the push rod in the MC that i have read about or even the pedal? it sorta pisses me off i put money and effort in something that is still completely out classed by something else stock.

RETed

The problem with vacuum pumps (i.e. Mity Vac's), is that they tend to suck air from the thread off the bleed valve.
I like to use some teflon tape to minimize this problem.
If you are getting small streams of bubbles, this might be from the bleed valve threads.


-Ted

patman

iTrader: (3)

rx7s do not have a very powerful brake assist... you have to push harder than a lot of cars.

try dirving it for a few miles, use the brakes a lot, then bleed again... driving tends to push the air into the calipers, so it bleeds right out after that.

pat