Sluggish braking

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audiocontr
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Sluggish braking

Post by audiocontr » Sun Sep 24, 2017 5:03 pm

I've found my breaks a little sluggish after off roading. I've ensured that they are cleaned out of any mud, and adjusted both 19mm adjusters per wheel to the point that they JUST release, but still it seems to take more foot pressure than normal to stop. I cannot lock them up by any means.

I bled the lines tonight and no change. Any suggestions?
1973 712m
(2) 1968 Haflingers 1 For Sale
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rmel
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Re: Sluggish braking

Post by rmel » Sun Sep 24, 2017 7:49 pm

Might want to pull the drums off and give a close inspection of the shoes etc and a clean
up with Brake cleaner. Esp, if the braking was noticeably different before and after wheeling.
Eliminate the possibility of of a fluid leak or trail crud on the shoes :wink:
Last edited by rmel on Sun Sep 24, 2017 9:27 pm, edited 1 time in total.
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TechMOGogy
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Re: Sluggish braking

Post by TechMOGogy » Sun Sep 24, 2017 9:15 pm

Agree plus their could be material (sand, small rocks, etc) in between the shoe lining and the drum
72 Pathfinder | 75 710M 2.7i | 94 350GDT | 96 350GDT Worker

Heinkeljb
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Re: Sluggish braking

Post by Heinkeljb » Mon Sep 25, 2017 1:47 am

Get a length of fencing wire, make a ring round one set of brake shoes to stop the brake shoes / pistons being forced out but allowing enough gap for them to move and get some one to press the brake pedal to make sure the wheel pistons move. They are prone to sticking in the bores.

John

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audiocontr
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Re: Sluggish braking

Post by audiocontr » Mon Sep 25, 2017 5:03 am

Thanks, I'll try the wire idea.

I have already pulled the drums and cleaned well. I was surprised how little build up was in them with as much mud as I had elsewhere.
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
Company Cars
2017 MKT
2018 F-150

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rmel
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Re: Sluggish braking

Post by rmel » Mon Sep 25, 2017 9:09 pm

One additional thought, you may have a leaking master cylinder seal.
This can result in no loss in fluid but fluid bypassing the master and a
resultant loss of force on the front slaves.

This happened to me this past winter. It was a complete fail of the front
brakes and not one drop of fluid was lost in the front brake reservoir. It
happened pretty fast, Brakes worked great then didn't work at all. After
I pulled the Master and tore it down it was then obvious the seal was
worn pretty badly. Replaced the Master with a new one and the old is
sitting around waiting for a rebuild someday :wink:

Just think'n.....
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rmel
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Re: Sluggish braking

Post by rmel » Tue Sep 26, 2017 3:12 pm

But wait :? The halfi does not have two brake circuits -- right?

So if the master seal is leaky, bypassing internally, there's no
secondary for any back pressure under foot. So if this is your
problem, simply maintaining pressure on the pedal it should leak
down to the floorboard then you know it's a bad master. I suspect
you would have noticed this already though.
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Heinkeljb
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Re: Sluggish braking

Post by Heinkeljb » Wed Sep 27, 2017 1:39 am

Most Haflingers are single circuit brakes.... The manual does show a dual circuit brake system which I though was for the "Utility" versions which carried addition loads as standard, but might also have been a "Pathfinder" American concession.

If there is very long pedal travel before hitting a "wall" then maybe the master cylinder piston is stuck at the bottom of the bore.

List of things that affect braking:-

No Fluid - reservoir empty or blocked
Master cylinder faulty
Metal brake lines "kinked"
Flexible brake hoses delaminating internally
Wheel cylinders stuck
Wheel cylinders leaking
Brake shoes stuck
Brake shoe material too thin
Brake shoe material glazed
Brake shoe material loose on shoes
Brake hub oval
brake hub worn beyond limit

So unfortunately, it is a question of starting at one end or the other and working your way through until you find the problem.

John

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audiocontr
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Re: Sluggish braking

Post by audiocontr » Wed Sep 27, 2017 4:49 am

Brake pedal has very little play, and I have to STAND on it to stop. Capital letters for emphasis.

I also learned that the pedal is not traveling far enough to turn on the brake lights, or there is an issue with brake lights... No brake lights now.

I'll look at the pedal assembly this weekend. Wonder if a stone lodged itself?
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
Company Cars
2017 MKT
2018 F-150

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Garrycol
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Re: Sluggish braking

Post by Garrycol » Wed Sep 27, 2017 6:15 am

Your issues are also symptomatic of the rubber brake hoses de-laminating on the inside not allowing fluid through and causing brake pressures to increase without much braking effort.

Garry
1973 Haflinger AP700
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1971 Jaguar Series 3 E-Type Conv
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TechMOGogy
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Re: Sluggish braking

Post by TechMOGogy » Wed Sep 27, 2017 7:53 am

Pathfinders has single circuit brakes too
72 Pathfinder | 75 710M 2.7i | 94 350GDT | 96 350GDT Worker

Heinkeljb
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Re: Sluggish braking

Post by Heinkeljb » Wed Sep 27, 2017 2:07 pm

audiocontr wrote:Brake pedal has very little play, and I have to STAND on it to stop. Capital letters for emphasis.

I also learned that the pedal is not traveling far enough to turn on the brake lights, or there is an issue with brake lights... No brake lights now.

I'll look at the pedal assembly this weekend. Wonder if a stone lodged itself?
If you are putting that much pressure on the pedal and it is not increasing the pressure of the brake fluid to the point the brake switch is activating, then start there! Pedal movement translates into a pin being pushed down the middle of the master cylinder and moving the piston down against a spring.

Possibilities:-

The pedal pivot rod has seized. Apply some PlusGas penetrating fluid followed by some thin oil.
The pin joint (hidden by the steering box saddle) might have seized. As above
The master cylinder piston might have seized in the bore. Dismantle master cylinder

You could try removing the brake switch, pushing on the pedal and seeing if you get a "fountain" of brake fluid out of the brake switch hole.

John

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audiocontr
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Re: Sluggish braking

Post by audiocontr » Sun Oct 01, 2017 4:11 pm

Fixed, but unsure exactly what fixed it...

1) Lights were coincidental. Someone did a horrible job of inserting the wires into the switch, and clamped down on the insulation. Contact was intermittent
1.5) Fluid shot out after removing the switch. Master cyl is fine, pedal is fine
2) Perfect pressure when bleeding brakes. I removed about three pedal presses per wheel.
3) Has new rubber brake lines
4) Took a red brillo pad to the pad surface and the drums.
5) Brake cleaner'd each wheel, and made sure to wiggle the pads to make sure they were not physically hung up

Rear right drum would not come off without turning in the pads slightly. I noticed the pads were pitted slightly on that wheel. Maybe thats what it was. Regardless, the pedal now depresses a tad further, and I can lock up the wheels on demand. Thanks for your help!
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
Company Cars
2017 MKT
2018 F-150

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Jimm391730
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Re: Sluggish braking

Post by Jimm391730 » Tue Oct 03, 2017 9:49 pm

Fluid shot out after removing the switch.
If the rod was out of adjustment and won't let the piston release all the way, the port to the reservoir would be blocked (opens only when the piston releases all the way). This would prevent any release pressure from venting back into the reservoir, and prevent getting more fluid in from the reservoir.
Jim M.
712W and 710M

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