Sn95 5 lug conversion on 89 brake problems help

[flymikemc]

I was wondering if anyone had done the SN95 5 lug conversion and had any problems with the front brakes slightly staying on or applying pressure to the rotor? I had my car jacked up and noticed that the front tires don't spin freely. It takes some abnormal effort to get them to turn. You don't really notice it when driving but it isn't normal. I thought it might be that I tightened the rotor bearings too much but after taking the wheel off I could move the lugs in the limited space of the rotor holes with no problem. However by putting pressure on the rotor it won't turn. So the brake pads are pushing against the rotors too much. Any thoughts on what I can do? Shave the pads? Its like there is residual line pressure from the master cylinder or something. :Thoughts?:

 

[Shakerhood]

the adjustment rod in your MC may be out of whack, there is a good formula for adjusting it on maximum motorsports page.

 

[NIKwoaC]

the adjustment rod in your MC may be out of whack, there is a good formula for adjusting it on maximum motorsports page.

Link?

 

[flymikemc]

I think your right about that. I was able to get the pads to back off a bit by pulling slightly on the rotor with the wheels off and that made the pads move and it spins nice and freely now. I put the brake on and it went back to taking both hands with a lot of force to move again. It must be that rod inside the MC you speak of.

 

[flymikemc]

I went on MM's page and couldn't find the link either. Could you have seen it somewhere else?

 

[Repostyle]

Step 1
Stop the engine before you test the free play in the pedal. Pump the brake twice to remove any vacuum. Press down lightly on the pedal with two fingers. You'll feel it stop abruptly; that's the master cylinder stopping the free play.

Step 2
Measure the distance from the top of the brake pedal to the floor with a ruler. Take a second measurement after you depress the pedal. Find the difference between the two numbers and you've found the amount of freeplay in your pedal. About 1/8 inch is average. If your pedal feels mushy, the difference probably is greater.

Step 3
Look at the back of the brake pedal until you see the point where it attaches to a push rod, which is the brake booster adjustment rod. Make a small dot with the liquid correction fluid on the bottom of the rod. This gives you a point of reference in case the rod turns when you loosen the nut.

Step 4
Loosen the nut at the top of the rod. Rotate the rod. Use the dot to realign the rod back to its original reference point if it moves.

Step 5
Turn the rod. When you turn it to the left, it tightens for less free play. Turning to the right does the opposite. You may need to use pliers to turn the rod.

Step 6
Tighten the nut to secure the rod again. Test the pedal with finger pressure to ensure you don't have to adjust the pedal height even more. If it feels within range, test drive the car.

 

[Shakerhood]

I went on MM's page and couldn't find the link either. Could you have seen it somewhere else?

Its definitely on MM, check out the section on MCs. It seems like that should be your problem, BTW the Hub Nut you mentioned in the Original Post is a one time use only nut.

Its under Installation Instructions, you will find the formula and how and where to measure.

 

[flymikemc]

Thanks for the info guys. I checked the brake pedal play and it has some free play in it so I don't think thats the problem. I plan on disconnecting the rod to make sure though.

 

[ddonaca351]

Well it's a little more of a longshot, but if youre brakes (the calipers anyhow) came from a used source / junkyard then the pistons and/or the bores may be coroded or gummed up with whatnot. (they will want to hang up and drag, instead of relaxing *slightly* when the pedal is released)

You can take the calipers off the rotor (you don't need to unhook the brakeline), pull the pads out, use a soft prybar or wooden spoon handle (dont tell the wife) or something to push the pistons back in the bore slightly. (don't go too crazy here, no need to cause other damage)

Then use a "hard" bristle toothbrush, and possibly some brakeclean to remove any gunk from the pistons and their bores.

Apply the brakes very gently, untill the piston *just* starts to protrude from the bore and clean the outside of the pistons as well.

If they show signs of light corosion, you can use some fine (read: SOFT) steel wool or light scotchbright to remove the surface fuzz. BE GENTLE... you dont want to do more harm than good.

Gently push them back in the bores again and reinstall.

See if that helps.

Dave

 

[flymikemc]

Thanks Dave. I will give that a shot.

 

[Shakerhood]

Thanks for the info guys. I checked the brake pedal play and it has some free play in it so I don't think thats the problem. I plan on disconnecting the rod to make sure though.

You wont know the proper measurement of the Rod, by the freeplay of the pedal.

 

[flymikemc]

You wont know the proper measurement of the Rod, by the freeplay of the pedal.

I must not be understanding the instructions you posted then. I thought we were looking for 1/8 th inch play on the pedal prior to the rod pushing on the MC. That way we are sure to not be preloading the MC.

 

[Tanus]

if its not the rod its probably the calipers, they're real easy to rebuild. let me know if you want any tips on doing this.

 

[flymikemc]

will do thanks

 

[89gt89]

Have you tried to bleed the lines again? I did the same conversion and the frond pads dragged horribly. The 2nd bleed took care of all probs.

 

[Shakerhood]

I must not be understanding the instructions you posted then. I thought we were looking for 1/8 th inch play on the pedal prior to the rod pushing on the MC. That way we are sure to not be preloading the MC.

I never gave you the instructions as they are on Maximum Motorsports webpage, even if the problem is possibly in your calipers you should still check that you have the pushrod set to the correct depth.

 

[flymikemc]

I never gave you the instructions as they are on Maximum Motorsports webpage, even if the problem is possibly in your calipers you should still check that you have the pushrod set to the correct depth.

I was mistaking the instructions Repostyle put up. I will test that pushrod, thanks

 

[flymikemc]

Have you tried to bleed the lines again? I did the same conversion and the frond pads dragged horribly. The 2nd bleed took care of all probs.

I will do that too. thanks

 

[SVT32VDOHC]

The torque on the bearings said like 250ft lbs when I installed a new one on a buddy's car. I didn't have a torque wrench that went up that high, so I just hammered on it with the impact, after I torqued it to 150ft lbs. Two years later...his wheel, has not fallen off, so I guess I did okay.

Did you buy the calipers used? You might have a sticky one. Were the slide pins greased? They should move freely. And the piston should compress in with little effort. I can use my thumbs on some cars and other require a small C-clamp with minimal force to turn in.