Line lock / frt brakes arent holdin..

[GrndNatnl]

Finished up my Hurst line lock install tonight.

My problem is, with a nice firm plant on the brake, line lock engaged, pedal released, the front brakes just dont seem to have enough clamping force to hold, and the car just pushes right through after easing into the throttle only a little.

Now it is on a concrete driveway with 275/50 M/T drag radials, but I would think I should still be able to brake the rear wheels loose without the rear brakes holding them.

This considering before I beefed up the rear brakes, I could power-brake burnout easiliy without overpowering the front brakes. The only thing I can think of is maybe re-bleed the front brakes? I forgot to hold the button on the combination valve in when I bled them tonight, but didnt think that was a big deal.

Replaced calipers several months ago, and new brake hoses tonight. Front brakes just seem to be weak. What gives?

 

[ajt86]

rebleed the brakes start from the passenger rear then driver rear then passenger front then driver front- you should have to hold the combo valve for manual bleeding on most cars thats only if you are using a pressure bleeder- as long as somones in the car pressing the pedal to bleed you should be fine. hows your brakes while driving- maybe you got a bad selinoid

 

[Turbo T/A 1543]

This is likely a stupid question, but did you install the solenoid on the line closest to the firewall? I experienced what you are when I installed one years ago...on the wrong line. Worked great on the back brakes though .

 

[GrndNatnl]

Yeah, the install is in the correct line.

The rear brakes will lock up in a hurry. I dont think I need to bleed them, only the fronts.

 

[Slow91z]

Matt try pumping them once or twice...Sometimes I have to do that to get enough pressure in the fronts to hold it.

Also remember when you are at the track the fronts will be on dry ground and the rears will e wet, so it will be much easier to hold.

 

[GrndNatnl]

Originally posted by Slow91z
Matt try pumping them once or twice...Sometimes I have to do that to get enough pressure in the fronts to hold it.

Also remember when you are at the track the fronts will be on dry ground and the rears will e wet, so it will be much easier to hold.

This is true.. I might do one more bleed, holding the combo valve button in this time, just for peace of mind. Then take it for a ride to warm the pads incase they're glazed. Then see how it acts.

My dad suggested the tight stall on top of the DR's on dry concrete might contribute to overpowering the front brakes. But I still dont see why the brakes wouldnt keep locked.

 

[Dan K]

Mine doesn't hold as well as I think it should either.
On the street it tends to push through if I don't build boost quick.
At the track it works perfectly though.
And this is on 28x11.5 ET Streets.

I've just left well enough alone.

 

[Nick Micale]

Correct install?

Originally posted by Turbo T/A 1543
This is likely a stupid question, but did you install the solenoid on the line closest to the firewall?........ .

Would "assume" you installed the line lock for racing at a track?

If there is an NHRA tech inspection you must pass, the solenoid must be installed AFTER the prop valve, not at the master cylinder.

The 2 lines from each front wheel should be installed directly into the solenoid.

 

[GrndNatnl]

Nick: Yes, but there arent any tracks that strict about line lock location around here (yet).

How would that work though as far as the prop valve is concerened? If you have the line from the master cyl going to the inlet on the linelock solenoid, then both brake lines comming from the out ports of the solenoid, you take away the front brakes from the prop valve. Doesnt that mess with the combo valve balance, and trigger the light? Would you just plug the holes on the valve? I'm not too clear on that matter.

I dont have to worry about that at any tracks around here though, nor at BG obviously.

 

[Nick Micale]

Do it right and safe

Originally posted by GrndNatnl
Nick: ..... If you have the line from the master cyl going to the inlet on the linelock solenoid, then both brake lines comming from the out ports of the solenoid, you take away the front brakes from the prop valve...........

A line from the prop valve to the solenoid applies [and holds when activated] the front brakes. Line from the M/C stays in the prop valve. A new line is used from prop to sol. Yes, plug the holes not used.

NHRA says do it this way because it is the proper and safe method.

When I do these installs, it is best to replace the left brake line with a longer one. Right side will fit ok.