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SVT Contour Brake Problem

T

TennTechMan

CEG'er
Joined
Dec 18, 2008
Messages
198
Location
Maryville, TN
I have a E0 SVT Contour. Ever since I bought it, the brake pedal doesn't do much to stop the car until the pedal gets really close to the floor. I have flushed the brake system with a power bleeder and the conventional pedal pumping method. I've run about 4 quarts of fluid through the entire system, and it's not really gotten any better. The brakes work well, but not until the pedal is about half way to the floor.

At some point prior to me purchasing the car, someone removed the ABS system from the car. The ABS module has been removed and bypassed. The master cylinder on the car has four ports on it. I've only ever seen master cylinders on CSVT's with 2 ports. From doing some research, it seems that the 4 port master cylinder came on cars without ABS. I guess someone thought they needed that since they were removing the ABS.

Any idea what could be causing this? I'm thinking of trying a different master cylinder this weekend and see if that fixes the problem.

On the rear brakes, where the hose meets the hard line, there is a cylinder-shaped thing a couple inches long. Any idea what this is?


Thanks in advance!
 
I'm not sure this is the correct answer but I give it a shot.
The 4 port MC may be smaller in diameter and so it moves less fluid then the 2 port ABS MC. That may be one reason for the long pedal.
The other reason is/may be is that the cars that came without ABS and got the 4 port MC were drum braked cars and they needed less fluid to work. Your car has rear disk brakes and needs more fluid moved.
 
The cylinder adapters on your rear brake lines are supposed to be there.
 
B3NN3TT said:
They act as proportioning valves, to alter brake bias.
Click to expand...

I know this to be correct info (prop valves), as I just converted my non-ABS rear drums ('95 Zetec) to rear discs from a CSVT (ABS, obviously) and had to delete these "prop valves" as my '95 has them installed at the MC.
 
jimbbski said:
The other reason is/may be is that the cars that came without ABS and got the 4 port MC were drum braked cars and they needed less fluid to work. Your car has rear disk brakes and needs more fluid moved.
Click to expand...

Not true, my last Contour (RIP) had 4 wheel disc but no ABS, something I dearly miss and regret not pulling to swap before it went for scrap.
 
TennTechMan said:
Are they somehow in the master cylinder? Or is it a similar looking parts mounted near the master cylinder?
Click to expand...

Good question you ask - They are not interchangeable with the rear mount brake prop valves, but they serve a similiar purpose/function. The are "sandwiched" between the brake hard lines and the master cylinder.
I will post a picture or two soon and get it posted.
 
TennTechMan said:
On the rear brakes, where the hose meets the hard line, there is a cylinder-shaped thing a couple inches long. Any idea what this is?
Thanks in advance!
Click to expand...
Might be a residual pressure valve, sometimes you find these on rear drum cars to keep the drum wheel cylinders from retracting the shoes away from the drum, but no way these should be on a rear disc car, and I don't recall anything between the rear hard lines and flex hoses on the rear of my 99 CSVT. Rear discs would work OK for a little while with a residual pressure valve, but they'd eventually drag themselves to death from overheating.

Does the MC/pedal go all the way to the floor, like hitting a mechanical stop, or does it stop short of full travel on the hydraulics? You can compare mechanical travel to hydraulic travel with a bleeder screw open front and rear for one pedal stroke.

Does the pedal go to the floor and then slowly creep down as you continue to apply pressure? If so, then the MC could be bypassing fluid, this would make for a soft pedal and poor brake feel.
 
gmorrell said:
Might be a residual pressure valve, sometimes you find these on rear drum cars to keep the drum wheel cylinders from retracting the shoes away from the drum, but no way these should be on a rear disc car, and I don't recall anything between the rear hard lines and flex hoses on the rear of my 99 CSVT. Rear discs would work OK for a little while with a residual pressure valve, but they'd eventually drag themselves to death from overheating.


Not following you here - drum brake construction requires return spings on the shoes themselves that return the shoes to static rest after wheel cylinder pressure is exerted outward, pressing the shoes against the drum surface.
Click to expand...
 
In some drum brake designs, the shoe return springs can cause the piston to retract more fully than desired, causing a long pedal. A residual pressure valve holds a few psi of fluid in the piston, preventing retraction. Drag racers often use them, usually a 2psi valve for disc brakes and a 10psi valve for drums, but they are found occasionally on drum brake street cars.
 
Thanks for the info - in my 40+ years around auto's, I have not come accross these in drum brakes...first I heard of this. Now I will NEVER forget my 1968 Corolla Sprinter with 4 wheel drums. What was unique to me (PIA) was that it had dual wheel cylinders in each backing plate. And these were all manual adjusted, seperate adjusters for the leading and trailing brake shoes - talk about a total pain!!! I spent many a day just adjusting brakes on this little car.
 
I just thought of another thing to check. Most Brake boosters has a rod that contacts the center of the master cylinder to transfer the motion from the brake pedal to the MC. Some of them are adjustable for length. It could be that the MC you installed has a piston that sits a bit deeper in the MC and every time you have to brake you have to take up that space. Perhaps all you need to do it remove the MC and see if you can adjust the push rod in the booster so that there is no gap. I have seen this happen on other cars when the MC was changed.
 
I think ^ may be onto something there. Also some EO svts did come with the residual pressure valves. My old one had one fail and i ended up drilling out the valve parts and used them as a union of sorts. Im not saying to do that as it in some way may be dangerous but it worked for me with no l affects
 
jimbbski said:
I just thought of another thing to check. Most Brake boosters has a rod that contacts the center of the master cylinder to transfer the motion from the brake pedal to the MC. Some of them are adjustable for length. It could be that the MC you installed has a piston that sits a bit deeper in the MC and every time you have to brake you have to take up that space. Perhaps all you need to do it remove the MC and see if you can adjust the push rod in the booster so that there is no gap. I have seen this happen on other cars when the MC was changed.
Click to expand...

Very true - I have even seen a vehicle with a "mounting block/spacer" sandwiched between the MC and the firewall, where it mounted to. This effectivley changed the pedal to push rod length, which was non-adjustable.
 
Nothing to really update yet. I've been too busy to actually do any work on it lately.

I thought about the adjustable rod. I've had to adjust that on my Lightning when I first got it. It's a pretty common thing on those trucks. I pulled the master cylinder away from the booster, and didn't see anything like what the Lightning has. If there's an adjustable rod, it's way in there.

I did drive the car a bunch last week though. I'm really thinking it's just that the master cylinder is worn. When I apply the brake, there is a barely noticeable pulse of brakes where it should be. The pedal then passes that point, and builds pressure a little lower.

My general plan is to still just try another master cylinder. During the swap, I'll look for a rod adjustment. If anything changes with the master cylinder swap, I'll disassemble the old one to see what's going on in there.
 
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