questions about installing brake hoses and master cylinder

[84pininfarinablack]

Im putting new brake hoses and a new master cylinder in my 84 and I wanted to ask if I am supposed to put something on the threads of the break hoses and break lines to master cylinder connection.. I havent done this since the 80s I cant remember if it was some kind of thread dope.. or grease.. or just brake fluid.. so i figured i would as you guys..
thanks for your help.

[pooldoctorstl]

No, just make sure they are clean going back in.

[pooldoctorstl]

One other thing....make sure you use new copper washers on the hoses.

[ga.spyder]

I always use a thin coating of grease on any thread,especially where you have steel into almninum.Bleeders and spark plugs are notorious for seizing.Anything I take off these cars,I lightly grease the threads when I put them back.A lot of people do use 'Anti-Seize'(thread dope)
Craig

[kuhndg]

One other thing....make sure you use new copper washers on the hoses.

I bought a set of performance brake lines from Mark yesterday and I was going to order new washers, too. He said unless the old ones are scored for some reason, with his experience using the existing washers they usually seat better then using new ones.

[radiopilot]

I replaced my brake MC and the hoses on my car two weeks ago and the front calipers were bleed just fine note: (to keep the bleed screw from seizing to the caliper I wrapped the threads in teflon tape- seen it on a Fiat page somewhere).
The rear calipers will not bleed for the life of me... I used the vaccum tool to pull the brake fluid/air... nada, I made a powerbrake fluid pressurized system using a new top on the brake resevoir... nada... it simply will not bleed... is there some secret to bleeding the rear brakes?

In the service book it does not specify to raise the rear of the car or anything... there are no fluid leaks anywhere... could the center hose be jammed? I opened the connection at the bottom of the center hose and it's got fluid, the connector junction has fluid, as soon as I opened the connection to the proportional valve it bleed, could the proportional valve be the culprit? It was working fine before I replaced the calipers... any thoughts?

Nick

[kilrwail]

To bleed the rears, you need to raise the rear of the car as high as possible and lower the front - to activate/open the brake compensator. There are lots of threads here covering the procedure in greater detail. Have fun!

[narfire]

When jacking the rear for brake bleeding, jack up from the axle. This keeps the proportioning valve open,jack up the body,it closes and no juice to the brakes. Glad you had juice at the center hose, then it now should get to the brakes.
The motive pressure bleeder has worked for me for the most part,then finished off with a helper and pedal pump.
Guinness helps with the brakes as well.

[azygoustoyou]

I was reading here and thought of something. I am going to remove the compensator and use Marks awesome braided line. Would that eliminate the need to raise the rear?

[pooldoctorstl]

Make sure the rear of the car is jacked up by the axle, not the body. The compensator is designed so that when you hit the brakes hard in a panic stop and the rear of the car lifts up, it stops fluid flow to the rear brakes and prevents lockup and you doing a 360 in the middle of the road. Not that that wouldn't be fun! So if the car is jacked up by the axle, you should get fluid to the rear brakes, and if you dont make sure the torsion bar from the axle to the compensator is free and not locked up in the bushings. If you still don't get fluid to the rear calipers check the compensator and the rear hoses.

[manoa matt]

That rear valve is often overlooked and seldom replaced. If you haven't replaced it and already rebuilt all the calipers and hoses the valve will become the weak link, and soon fail resulting in your rear calipers dragging. Replace the valve, Fiat engineers put it there for a GOOD reason. Also the valve is cheaper than the hose that replaces it.

To properly bleed the rear brakes the rear brake caliper piston must be oriented in the right direction. The line inscribed on the face of the piston must be horizontal and on the top side with the caliper held in the normal position. Jack up the rear of the car and support it with jack stands under the axle. Disconnect the rear comp valve linkage at the attachment point to the axle housing. Push up and support that bar to fully open the valve while bleeding.

Did you bench bleed the master cylinder before installation?

[radiopilot]

Good advice...

Question does the car really need to be raised or can I undo the rod from the lever on the axle bracket, pull down or up on it (which direction?) to open the valve while bleeding the brakes... is that an option? I think you guys are spot on... the proportioning valve is not open to allow fluid to get the rear calipers... I've been driving the car lightly and it seems like the fluid is getting to the rear brakes but the brake pedal still feels spongy... still has air in the rear lines, I raised the front and the brakes grab solid so they are fine and according to the service manual the front & rear lines are independent when bleeding the brakes.

The proportional valve was replaced with the calipers so it's a new one, the only brake items not replaced was the center brake line and the brake metal tubes... everything else was new... by the way Advanced Auto has the front calipers for $29.00 plus $5.00 for the refundable core, the rear calipers are $35.00 with the refundable $5.00 core. They are rebfurbished with new components and look excellent and clean (what I wanted) as I painted them with yellow ceramic caliper paint from Eastwood... they look excellent... but are hidden by the turbo wheels so I may be looking for some new wheels soon to show off those yellow calipers.

Nick

[radiopilot]

Double post

[pooldoctorstl]

Matt is right. Don't remove the comp valve, just make sure it is working and adjusted correctly. They are like a caliper in that there is a piston in it that can freeze up. Chances are that if your calipers were bad so is the comp valve. Mine was. Here is the page from my manual that I used.

[mdrburchette]

Good of you to post the instructions for adjusting the proportioning valve. That, as well as the proper adjustment of the actuating rod for the master cylinder is important for good braking. I've never bench bled an m/c and haven't had a problem, but I guess it'll eliminate a potential one.