'96 Sable Brake Problem - Leaking Fluid MC?

[benjamming]

1996 Mercury Sable 'U' code Vulcan OHV 12-valve engine GS trim (not sure if it is flex fuel) with brake problems. It immediately pulls hard to the right with brake applied. Reservoir was very low so leak somewhere. I filled reservoir & started bleeding the left front. It doesn't get better meaning that very little fluid comes out of bleeder screw. I trace the brake line & it appears that there is brake fluid on the surface that the master cylinder bolts to (power brake booster). Does this all sound right so far? If so, I plan on replacing the master cyclinder but should I also replace the power brake booster? I haven't been able to find a master cylinder rebuild kit. Should I look further at that? All reman master cylinders came less reservoir & all new master cylinders came with a reservoir. I was only able to find a power brake booster with master cylinder from Carquest. The only new power brake booster available was from dealership. I've called the parts stores & dealerships: AutoZone $40 reman Fenco master cylinder $60 new Fenco master cylinder $53 A1-Cardone reman lifetime power brake booster Advance Auto Parts $38 reman Cardone lifetime master cylinder $52 new Cardone lifetime master cylinder $52 reman Cardone lifetime power brake booster O-Reilly $38 reman Cardone lifetime master cylinder $58 new Brake Best master cylinder $53 reman Cardone lifetime power brake booster Napa $41 reman True Stop lifetime master cylinder $59 new United lifetime master cylinder $79 reman Cardone lifetime power brake booster Carquest $44 reman Cardone lifetime master cylinder $61 new Cardone lifetime master cylinder $75 reman Cardone power brake booster with master cylinder Local dealership #1 $235 new master cylinder 12month/12k mile warranty $198 new power brake booster same warranty Local dealership #2 master cylinder not available from Ford - go aftermarket $206 new power brake booster for non flex-fuel vehicle; discontinued for flex fuel vehicle - go aftermarket I'm not buying from Rockauto so no need to suggest. Y2K Ford parts is down right now. Any tips on replacing a master cylinder as I've never done this on any vehicle before. It appears to be a couple bolts, two brake lines, & o-rings. I plan on soaking the brake lines with penetrant since I doubt they have ever been touched. What about bleeding the master cylinder? How is that properly done? I assume that a gravity bleed would be best once installed? I don't own any pressure bleeders, etc. Is this a common problem with this vehicle? Is it common for most vehicles with this age/mileage? Thanks.

 

[Steve S]

Did you pull the wheels and inspect the brakes?

 

[benjamming]

Oh yeah. I assume you mean the pads when you say brakes? If so, the pads are fine. Why?

 

[eljefino]

I wonder if you have two seperate problems. Sometimes the plastic reservoir over the MC leaks or its o-ring leaks. It is not under pressure and therefore underbuilt. For braking you could have sticky caliper pins or the pads are locked up in their guides. Did you stab the pedal with the bleeder open? Sometimes you get a chunk of rust in the bleeder itself which will come loose with sufficient hydraulic pressure.

 

[The Critic]

Originally Posted By: benjamming

Oh yeah. I assume you mean the pads when you say brakes? If so, the pads are fine. Why?

If you have a brake pull, I would also check for any seizing calipers. Master cylinders can be challenging to replace. Does this vehicle have ABS? If so, you may need a scan tool to perform an automated bleed procedure. Even if it does not have ABS, I would consult the factory service manual before starting to see if you will need any scan tools. AutoZone's website may give you the info. Also, prior to installing the master cylinder you will need to bench bleed it. You may want to invest in one of these syringes: http://www.underhoodservice.com/Article/46616/tech_tip_priming_a_new_master_cylinder.aspx

 

[benjamming]

Oh yeah, about the brakes pulling. The right side had brake dust on the bake of the pad but the left side had (virtually) none. It does sound like 2 problems. I was focusing more on the master cylinder issue, sorry. The vehicle does have ABS. The pic in that link doesn't show up for me. Does anyone have it? AutoZone ABS bleed procedure says that a New Generation Star (NGS) tester or equivalent scan tool is required to bleed the ABS. I have neither. What are my options? Exercise ABS manually & then bleed system again? Does the groove seal in the brake booster come with a new master cylinder? AutoZone Master Cylinder Procedure "Manufacture or purchase bleeding tubes and install them on the master cylinder as illustrated." What are these exactly? Of course, it's not illustrated. Anyone have a picture of this? Where are they connected?

 

[The Critic]

Originally Posted By: benjamming

Oh yeah, about the brakes pulling. The right side had brake dust on the bake of the pad but the left side had (virtually) none. It does sound like 2 problems. I was focusing more on the master cylinder issue, sorry.

In that case I would install a set of semi-loaded calipers with new brackets. Don't forget to clean and adjust the rear drums as well.

Originally Posted By: benjamming

says that a New Generation Star (NGS) tester or equivalent scan tool is required to bleed the ABS. I have neither. What are my options? Exercise ABS manually & then bleed system again?

You probably need an aftermarket scan tool with support for the Ford service bleed procedure. The autoenginuity system is $250 for the hardware and $150 for the Ford OE expansion. Since this isn't your car you may want to do the work and have a shop bleed the system for safety reasons. Manually exercising the brakes may be time consuming and may not always remove all of the air.

 

[benjamming]

It doesn't seem that the gasket between the master cylinder & power brake booster comes with either reman part. A snap ring is the first thing on the end of the m/c so that wouldn't seal. I assume there are gaskets where the reservoir fits on the m/c but the reman parts didn't have those either. They did come with clear tubing for bleeding the m/c. No aftermarket parts stores had new master cylinders or power brake boosters to inspect for these gaskets. Dorman p/n 42098 is for the cap gasket so that doesn't seem right. Any other ideas/leads for gaskets since it sure does appear that is what is leaking? I have also learned that the reservoir had been run low for an unknown amount of time, but not too long after the low brake fluid light illuminated. A couple pictures from a camera phone that turned out poorly but here they are nonetheless. This second picture is taken from the wheel well looking up to where the m/c bolts to the power brake booster. You can see where it is running down the booster.

 

[eljefino]

I don't know brakes that well but I don't expect a need for a gasket between MC and booster. Should just be a pushrod, whatever seals the brake fluid behind the pushrod will be part of the MC. As for the reservoir, should just be an o-ring and a press fit.

 

[willix]

Its a typical problem overlooked on the Ford Taurus that the brake hose at the wheels corrode at the clasp that anchors it to the strut. This chokes off the hose causing very retricted flow to the caliper and in addition the caliper becomes pressure locked & drags the brakes releasing eventually after time. The rear brakes have aditional problems with the e-brakes malfunctioning due to corrosion. Slider pins also are known to get suck. These issues will cause pulling rt. of lf. If you take a quick feel of the wheel, not the tire, you may find one wheel cooler on that axle. don't burn yourself. Calipers are cheap. Rotors are $20 each.

 

[RH+G]

It looks like your master cylinder in leaking into the brake booster. U will need to change the master cylinder ASAP because the brake fluid that is going into the booster is damaging it. If its been leaking in their for a while y would need to change the booster too. That may not fix your pulling issue thou. That might be a seperate problem

 

[benjamming]

eljefino, Thanks about the gasket being internal to the m/c. That is certainly what is leaking so I feel confident a new m/c will fix this particular problem. I bought the new master cylinder with reservoir from Carquest (made by Bendix) for $61.55 including tax. It didn't come with the vinyl tubing to bleed the master cylinder like the reman units so he included a couple of those as well. It was assembled in USA (which I take to mean that the reservoir was placed on the cylinder in the US. The master cylinder also had USA stamped on it. How do I know if the power brake booster needs to be replaced? There has ~ 1 qt of brake fluid added to the system over a good year. Anyone have a good pictorial that they can recommend for how to properly bleed the master cylinder?

 

[RH+G]

Technically anytime the master cylinder has leaked into the booster it should replaced. Their is no set way to know thou. If it fails then u have to replace

 

[benjamming]

http://www.denlorstools.com/home/dt1/page_7445/automotive_brake_bleeding_exclusive_tech_article.html http://www.youtube.com/watch?v=qgf8X4ZzBfg

 

[benjamming]

Well, replaced the master cylinder today sans flare nut wrenches but my Wright open end had no problems after spraying w/ penetrant (phew - set of flare nut wrenches will be ordered soon). Cleaned the power brake booster up as well as possible. Bench bled the m/c, installed, bled the primary & secondary lines at the m/c, & then bled the 4 corners. Brakes work great! Very good pedal; much better than my '94 Grand Am (am jealous of a '96 Sable - pretty sad huh?). I live on a mountain so the first test was a doosy (foot on emergency brake just in case!) but no problems. I used Motorcraft DOT 3 to fill the reservoir, & then followed with AMSOIL DOT 4 to bleed.