1991 Loyale Air in brake line

[saltytheseadog]

I've been repairing the brakes of a loyale. So far I've replaced the Master Cylinder, the brake shoes, and the wheel cylinders. Drums are both on.  Bled right rear brake, came clear of air after half dozen pumps of brake pedal. At  Left rear after 30 -40 pumps of pedal it continues to produce air. Pumping up brakes indicates air in line as pressure builds up with pumping. I can't detect any system leaks and would expect to hear noises , see fluid dripping if a line were corroded through. I clamped down on the reservoir to see if the new grommets that came with the master cylinder were leaking but made no difference. I have a clear hose on the bleed nipple and every pump is 10 to 12 inches of brake line so the line should be clear. Any comments?

[el_freddo]

Have you bled the front brakes yet? 

With the redundancy system from memory you should bleed the front first then then opposite rear second, then the other front followed by the other rear brake. There may be a particular side to start on too, the FSM or Haynes should outline what the procedure is.

Have you got all the air out of the master cylinder too? 

Cheers 

Bennie

[saltytheseadog]

The way to bleed I've been told is start with the furthest away from MC, then next furthest etc.

Haven't bled MC, didn't notice any bleed valve on it. Is there a procedure for this?

Just checked with Haynes; right rear,left front,left rear, right front.

Ok got it. Try bleeding MC tomorrow and follow proper order.

Thanks I'll report back

[czny]

You need to bleed the lines closest to the master cylinder first(front calipers), then the rear.

If you do the opposite you may siphon air from the short un-bled lines where the lines connect at tees, hill holder, etc.

Bleed M/C with lines just loosened a little until fluid pushes out, then tighten them up. Put an oil pan underneath to catch the mess. Hose it down with brake cleaner afterward.

Bleed order is Left front, then right rear. Right front, then left rear. Get a one man bleeder kit with a check valve in it. Put the valve end in a small plastic bottle with a little brake fluid in it to stop air from going back up the bleeder hose. Pump slowly with full strokes of the pedal 6 to 8 times at each wheel then check the reservoir after closing the bleeder.

Not trying to discount what you know of bleeding brakes, just repeating what has worked for me since the 70's when working alone. Used to be a NIASE dealer mechanic.

Good luck!

[idosubaru]

Ive used up to almost 96 ounces (3 big bottles) to bleed an open system.  It Can take forever.  Like 10 or 20 pumps per corner  

the piston seals can leak and are covered by the piston bolts so you can’t see if they’re leaking.
 

if there’s rusty lines thr rust can have thick layers of rust but no holes, and the fluid just seeps through and wets the rust rather than drips until a lot of fluid is lost. Usually above thr gas tank where you can’t see it. 

[saltytheseadog]

Today we bled the MC and found some air in rear cyl. but mostly clear. Followed Haynes recommended bleeding order and all except left rear were clear of air. Left rear line had a lot of air in it but finally cleared out. We will give it another round tomorrow when our brake fluid supply is replenished but most air is gone now.

I'll try the order czny suggests, it is also the order used in How to keep your Subaru alive for OHC cars

[idosubaru]

1 hour ago, saltytheseadog said:

Today we bled the MC and found some air in rear cyl. but mostly clear. Followed Haynes recommended bleeding order and all except left rear were clear of air. Left rear line had a lot of air in it but finally cleared out. We will give it another round tomorrow when our brake fluid supply is replenished but most air is gone now.

I'll try the order czny suggests, it is also the order used in How to keep your Subaru alive for OHC cars

How long and badly the system is as open makes a difference. If I swap a caliper real quick I can bleed quick. If I have the system open for a long time and lots of fluid comes out and MC replaced it can take waaay longer than expected. I wouldn’t be surprised at all if you keep bleeding and eventually get it all out. 
 

or you could have an issue. Check for rust or wetness above gas tank where lines run and fluid loss past caliper piston seal under the boot. 

[czny]

Just had to replace both front calipers, pads & rotors(F&R) on my 87 GL this summer. R front piston had seized so I only had half braking, pads were dragging. At the time, could only find a Nugeon R caliper and a Cardone L caliper. Replaced the M/C, and hillholder too. I had a donor vehicle here for that.

Might have to make brake parts corrosion an annual thing with the road salts here... 

It took 2 big bottles of brake fluid to do the job front & rear (did rear disc conversion long ago). After all that, discovered the LH parking brake cable wasn't returning correctly. Had to pull off that Cardone L caliper only to find the caliper parking brake lever wasn't returning - Cardone in Ontario Calif had left the return spring out! 🤬

Haynes manual shows how to make & use a special tool to compress the spring washers to get at the return spring and fulcrum. Robbed one from my old caliper to get that done.

Then after yet another 2 bottles of brake fluid later I was done!

If you have to replace front calipers , do it in L&R pairs, make sure the caliper pins get brake lube or antiseize with new or good pin boots, and don't buy Cardone calipers!

Rockauto lists Raybestos and Nugeon again, thankfully!

[Numbchux]

Master Cylinders should be bench bled before installation. so you've likely pushed a lot of air into the system.

If your car has a hill holder (definitely on MT GLs, I never had a MT Loyale), there's a bleeder on that.

[czny]

2 hours ago, Numbchux said:

Master Cylinders should be bench bled before installation. so you've likely pushed a lot of air into the system.

If your car has a hill holder (definitely on MT GLs, I never had a MT Loyale), there's a bleeder on that.

https://www.amazon.com/Dorman-14151-Master-Cylinder-Bleeding/dp/B08M4D9HSB/ref=sr_1_5?crid=2KWX4S30D88K6&keywords=brake+master+cylinder+bench+bleeder+kit&qid=1701377743&sprefix=master+cylinder+bench+bleeder+kit%2Caps%2C201&sr=8-5

[saltytheseadog]

This brake system still has air in it or air getting into it. I went around bleeding the lines starting at the M/C twice through . All the bleeders are clear of air except the  left rear which I have collected a half pint of fluid from and still no end in sight from air bubbles in the fluid. I'm thinking that the air is somehow getting into the system but can't think how. If there were even a pinhole leak in a line shouldn't there be fluid escaping from said hole when under pressure. There must be something else going on for that much air in the line.

[czny]

14 hours ago, saltytheseadog said:

This brake system still has air in it or air getting into it. I went around bleeding the lines starting at the M/C twice through . All the bleeders are clear of air except the  left rear which I have collected a half pint of fluid from and still no end in sight from air bubbles in the fluid. I'm thinking that the air is somehow getting into the system but can't think how. If there were even a pinhole leak in a line shouldn't there be fluid escaping from said hole when under pressure. There must be something else going on for that much air in the line.

Did you check out the rear rubber brake lines between the cross member and the swing arms for cracks or splits at the ends?

https://www.rockauto.com/en/catalog/subaru,1991,loyale,1.8l+h4,1270112,brake+&+wheel+hub,brake+hose,1792

Edited January 7 by czny

[saltytheseadog]

I don't see signs of leakage there. Air in would mean fluid out wouldn't it ? I may replace them because I can't think of anything else to do.

[czny]

6 hours ago, saltytheseadog said:

I don't see signs of leakage there. Air in would mean fluid out wouldn't it ? I may replace them because I can't think of anything else to do.

Don't forget the brake proportioning valve is also back there. I had one leak fluid from the end seal but only on hard braking only.