No brake fluid to front brakes after caliper rebuild!

[Turbofiat124]

This is a followup to a braking issue I was having with my Spider that started last year. I finally got around to working on the brakes but now I have no brakes.

The problem was under hard braking my Spider would pull to the right for a split second then correct itself. Like there was a delay action in the left caliper.

From my past experience this is usually a sign that there is either crud buildup between the piston, seal and caliper or the mating surfaces of sliders are corroded and need to be cleaned and lubed. A collapsed brake hose would cause sticking all the time then go away after a few minutes. So I have fixed this sort of problem in the past.

Nothing appeared wrong with the steering components like a worn tie rod.

So today I took the front calipers apart. I didn't find anything unusual with the caliper I suspected was sticking. The driver's side caliper looked fine but the passenger side caliper did have some "white crust" inside the dust cover. Like dried brake fluid. Or could have been corrosion.

So I cleaned off the dried caliper grease off the sliders, lubed everything like I always do and slapped the calipers back on.

As I've done many times before, I got out my Gunson's Easy Bleeder (Google it!) and hooked it up. I've used this tool many times on three different cars. I set the tire pressure at 10 PSI, otherwise it leaks like hell. Well still does at 10 PSI but I can deal with it.

I open up the bleeder screw on the driver's side and no fluid comes out. So I tried the other side. No fluid on that side either.

I start pumping the brake pedal. Normally the pedal should start getting firmer but it never builds up any pressure.

I had my wife pump the brakes, Still nothing!

I removed the bleeder screws from the calipers and had her pump the brakes. At this point brake fluid should be squirting out of the calipers like gangbusters.

Also never saw the calipers "wiggle" as she was pumping.

I extracted the piston from the driver's side caliper and there was not a drop of brake fluid inside the caliper. So no fluid is getting to the calipers at all.

So is there a restriction between the master cylinder and caliper inside the lines?

Aren't the front lines independent of one another? I wouldn't imagine both front circuits would crap out at the same time.

I loosened the front lines at the master cylinder and had my wife pump the brakes. I expected to see lots of fluid shoot out but nothing.

I finally did see a few drops of brake fluid from the caliper hose. Probably residual fluid.

I've come to the conclusion that the master cylinder has just crapped out for no apparent reason.

Before I pulled the calipers, I had a nice firm pedal, just a delay action in what I thought was the front driver's side caliper.

So perhaps this delay action was some sort of tell tale sign the master cylinder was about the crap out?

I've replaced several Fiat/Yugo master cylinders and have never seen one actually fail. Typically the rear seal starts leaking brake fluid but the pedal is still firm and the brakes still work.

I have not checked to see if any fluid comes from the rear brakes. I just have the front end supported on jackstands.

What am I missing?

[124JOE]

it seems to be a bad MC replace it

[Rambo]

Are you bleeding with vacuum assistance? I cant say why but the last few times i bled my brakes i had more fluid flow without the engine running. Id try that if you haven't already.

[Turbofiat124]

Are you bleeding with vacuum assistance? I cant say why but the last few times i bled my brakes i had more fluid flow without the engine running. Id try that if you haven't already.

No, I've never tried bleeding the brakes with the engine running.

Maybe the master cylinder was getting weak and when I released the pressure by disconnecting the calipers, no longer allowed it build up any pressure? I wonder if that's possible?

[124JOE]

you could try removing the line from the MC and put your finger over it
while she pumps the pedal
it should push air out without pulling air in
then fluid out.i did this on my bike to prime the MC

[Turbofiat124]

you could try removing the line from the MC and put your finger over it
while she pumps the pedal
it should push air out without pulling air in
then fluid out.i did this on my bike to prime the MC

I did loosen the lines going to the front brakes and had her pump the brake pedal but never saw any fluid come out of the threaded ports. Neither did the level drop in the reservoir. So either no fluid is not getting into the master cylinder or no fluid is getting out.

I wondered if the hoses between the reservoir and master cylinder may have collapsed inside and no fluid is getting to the master cylinder? The hoses are maybe 10 years old. I am sure I used to correct hose that is rated for DOT 3 brake fluid. Unless the guy I bought them from off Ebay ripped me off and sold me fuel line hoses.

But since I used my Gunson tool to force fluid through the hoses, looks to me that would have worked.

I guess I could replace the hoses first before replacing the master cylinder to see if this works.

My Trabant uses an oddball size hose that runs from the reservoir to the master cylinder. 8mm hose won't fit over the nipples. From my memory the nipples were like 9mm.

On that car I ended up using some 3/8" poly tubing and heated the ends with a hair dryer so they were more pliable and would slip over the nipples easier. So far they have held up. But eventually when this hose comes in contact with brake fluid or gasoline (in the case of my mini-bike) it becomes rock hard and has to be discarded if it's removed. But it's cheap so it's not a big deal.

[Turbofiat124]

Well, here is a new one on me. I thought I'd seen it all when it comes to Fiat brake problems.

So after installing a new master cylinder, same problem: I get fluid coming out of the MS where the lines screw in when I pumped the brake pedal but still no fluid to the front calipers.

Then I made sure I was actually getting fluid to the MS by disconnecting the hoses from the reservoir at the MS. That checked out OK.

So I came to the conclusion that the brake hoses were bad. Luckily I had some new ones laying around. Now I got brake fluid to the front calipers. I blew through the old ones and somehow there were restricted.

Typically when a brake hose is bad, it collapses and acts as a check valve and one of the front calipers stick. Then after a few minutes the pressure releases.

This is the first time I've ever seen where I could not get fluid to the front calipers due to the brake hoses. Apparently fluid was getting to the front brakes but not after I disconnected the calipers. Maybe the fronts were barely working at all.

I bleed the rears while I was at it. No issues getting fluid to the rear calipers.

As usual the pedal goes about 1" from the floor as it always had. I did not want to adjust the rod (from the Carl Friedman incident).

So choke that one up.

[DieselSpider]

Well, here is a new one on me. I thought I'd seen it all when it comes to Fiat brake problems.

So after installing a new master cylinder, same problem: I get fluid coming out of the MS where the lines screw in when I pumped the brake pedal but still no fluid to the front calipers.

Then I made sure I was actually getting fluid to the MS by disconnecting the hoses from the reservoir at the MS. That checked out OK.

So I came to the conclusion that the brake hoses were bad. Luckily I had some new ones laying around. Now I got brake fluid to the front calipers. I blew through the old ones and somehow there were restricted.

Typically when a brake hose is bad, it collapses and acts as a check valve and one of the front calipers stick. Then after a few minutes the pressure releases.

This is the first time I've ever seen where I could not get fluid to the front calipers due to the brake hoses. Apparently fluid was getting to the front brakes but not after I disconnected the calipers. Maybe the fronts were barely working at all.

I bleed the rears while I was at it. No issues getting fluid to the rear calipers.

As usual the pedal goes about 1" from the floor as it always had. I did not want to adjust the rod (from the Carl Friedman incident).

So choke that one up.

With all the variations of brake fluids this appears to be happening more often lately. Stay with plain vanilla DOT 3 and do not switch brands to play it safe. If you put in incompatible fluids combined they can cause the hoses to swell internally with the centers turning to putty. When you flush the system you still should stay with what was in there before or this can still occur. This happened to mine when Tire Kingdom mixed fluids and I lost all hoses front to rear along with the new master cylinder. When I ran a mechanics wire through the damaged hoses the centers came out in a solid stream like old black caulking.

[Turbofiat124]

I figured all DOT 3 brake fluids were the same. It's not like there are any special additives in it like oil or antifreeze.

I usually just buy Wal-Mart Tech 2000.