Front end lock-up

Front end lock-up

Daz
Daz

May 5th, 2008, 4:33 pm #1

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
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JJ
JJ

May 5th, 2008, 6:03 pm #2

I have only had this happen in a panic stop scenario and its usually an understeer moment...

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Joined: August 17th, 2005, 1:47 pm

May 5th, 2008, 7:58 pm #3

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
that's a new one on me, Daz...YEARS of driving X's, and not had this happen ever. There are proportioning valves that you can buy and set up the brake bias, but- not really needed, if you're only street-driving?

maybe someone with more knowledge can help on this one...sorry.


Greg S
Finally DIVORCED!
"SOLO X"
1300 Series Speciale Modified a bit
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Joined: August 7th, 2006, 3:12 pm

May 5th, 2008, 9:01 pm #4

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
...something uniquely wrong with your '79. I had an '80 and now have an '84 and '86 and none have had a brake lock-up issue.

Was this a street, or track car?... Modified?....


Jim W. (in the Northeast)
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htf
Joined: May 5th, 2001, 4:29 pm

May 5th, 2008, 9:18 pm #5




HaXD
Herzel, in Israel

WhiteX
The late Green '85 X1/9
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Ian Lawson (NZ)
Ian Lawson (NZ)

May 5th, 2008, 10:14 pm #6

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
<<<<<< the car was particularly prone to the fronts locking at the slightest touch,>>>>>>

I have experienced front brake lockup on my '78 1300 X only twice, and both times were when approaching traffic lights which changed to RED when I SHOULD have slowed down a little earlier.
In a typical "whoops, I'm not going to make it" reaction, and consequently braking heavily, did my X lock up the front brakes.
NOT a comfortable feeling, I must say!!

But if your front brakes are locking up "at the slightest touch" as you mentioned in your post, I suspect that you have something more seriously wrong.
Have you got mis-matched pads (front to rear)??

Certainly needs looking into!

cheers, Ian - NZ
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Joined: March 8th, 2005, 3:26 am

May 5th, 2008, 10:36 pm #7

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
Hi - I'm basically new to this site and I don't want to create a controversy or anything. (OK -- I do....)

LOL!

You guys must drive like sissies!

ALL X1/9s lock up the front brakes under hard breaking -- add a little gravel or any kind of bumps or less traction on the road and it might not even take hard breaking.

The best solution to this is to add a proportioning valve in the line -- I've posted on this before (years ago).

http://www.network54.com/Forum/12159/me ... e+-+Summit

I run the front calipers on both ends of my race car for a little bit extra but then you lose the handbrake.

PEACE!

--> Alex (SoCal)
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Joined: November 21st, 2007, 2:40 am

May 5th, 2008, 11:05 pm #8

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
Have had this "issue" on both my 85 and 86. Under severe braking, and as Alex stated, gravel, or crappy roads, like the ones I drove on out in Elsinore. In my experience, the car skips and skids.

Under normal driving/braking and good roads, hardly ever happens. But hard braking is part of the "normal" driving experience. It can happen but not always.

RMMJ
1986 Bertone X1/9 a.k.a BlueTooth
www.socalx.com
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DougESmith
DougESmith

May 5th, 2008, 11:32 pm #9

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
to lock up the brakes on all my X1/9s.

Thinking out of the box.... you say you replaced all of the lines, your line from the master to the rear could be blocked or the master defective, effectivly boosting the power to the front by under powering the rear... just a thought.

oh, would you be running really old really skinny hard rubber on the car?
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Andrew Coles
Andrew Coles

May 5th, 2008, 11:51 pm #10

any one experienced this on their X and if so what did you do about it?
I have not got my '89 on the road yet and all hydraulics, pipes, pads and discs have been renewed front and rear.....
How ever, as I recall years ago when I had my '79, the car was particularly prone to the fronts locking at the slightest touch, creating many a 'brown pants' moment, so just wondered if mods like proportioning valves or bigger rear calipers etc have been used.
Or will the new stock and tyres cause this not to happen?


Drive safe!
have definetly had this, but as some others have said not all the time and only under extremely heavy braking.

One day was on my favourite stretch of twisty road (Norton Summit for those Adelaidians:) ) on the flat bit down the bottom, swinging through the corners at about probably 90-100kmh. As it turns out there were roadworks around one blind corner - except no warning signs at all! Maybe blown over, someone stole, never out? All I know is that I came around a blind corner to find a train of stopped cars. The fronts locked up (which I was kinda expecting), however due to sheer luck probably I was able to cadence brake and stop in time. Had the guy in the Celica (last car in the train) fairly worried though. Have also had them lock on the track as well.

Im planning to get around this hopefully by using equal sized calipers on front and rear, in my case 4 piston's all round, and a bias valve to modulate pressure. However these things only mask the problem (quite well) but you cant change simple physics - there isnt a hell of a lot of weight up front so eventually the fronts will have a tendancy to lock.

I guess just be aware of it and drive accordingly on loose surfaces
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