All i did was flush...
 
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All i did was flush the bloody radiator...


David Beck
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...and the brakes are a problem.

Quick summary of any relevant information (or not!)

  • Car last used to go to Bicester a couple of weeks ago. Had a squeaky moment on the way back when a young lad on the inside line of a fast island decided to change his mind and turned right, a quick brake lock up, and rapid diversion for me to also go write avoided a collision, this involved heavy use of the brakes but had no other issues driving home.
  • Yesterday decided to flush the system out, one of many steps to try and improve cooling, as part of this I also played with some new toys, namely a jack and four jack stands, as such I put the car on four jack stands to make the draining just a bit easier.
  •  I also had some hydraulic skates for my birthday and the car has been on and off those the last week or so.

After I had got the car back on the floor I went to push forwards and could barely move her, same for backwards. After some head scratching and a quick chat with Paul I checked all the brake pipes where I had jacked up and all was fine. I then looked at the brake pedal and puled it very slightly towards me, this was enough to release the brakes again.

Any downward pressure would cause them to bind until a very light pull freed them again.

I assume that either

The pedal return spring has given up the ghost?

Something in the hydraulics is not doing what it is supposed to?

Any opinions welcome.

Not having had chance to work on the car before if anyone can offer any documentation or advice on removing the pedals and locating a new spring (if that is the issue) then everything will help.

Thanks

Dave

The Cobra Register - Founder Member


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Roger King
(@roger-king)
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Joined: 7 years ago
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Dave, it’s not going to be a return spring on the pedal as it shouldn’t be possible for the hydraulics to lock on. Assuming you have the twin master setup, you need to jack it up again and ascertain whether it is fronts or rears that are sticking on. It sounds like one of the master cylinders is not releasing pressure properly. 

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Several old bangers, which used to include a 289
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Barry Jones
(@289-baz)
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Joined: 6 years ago
Posts: 82
 

Exactly what Roger said, we have had the same problem with over winter storage gum builds up the bore behind the rubber boot, it is just enough to hold the piston forward ( brakes on), it doesn't have to be much to stop you pushing a car. To rectify it dose mean a brake master strip down, but as Roger said you need to find out if it's the front or rear brakes binding. 


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David Beck
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Topic starter  

Thanks both. One thing I did do yesterday was to was to lubricate all of the mechanisms as they have been flooded occasionally!

When I put the car on the jacks and tried each wheel the resistance was far less than yesterday, I could spin them with my hands, the fronts offered more resistance however given the bias you would expect that anyway.

After that I then dropped it back onto the floor and  found that although there was still some resistance it was nothing like yesterdays. 

Not entirely sure but it could just be gunk on the shaft enough to stop the pedal coming back, something Gerry mentioned on the phone he has seen before. 

Will take it for a gentle run tomorrow evening and see how things go.

Thanks

Dave

 

The Cobra Register - Founder Member


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Roger King
(@roger-king)
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With it jacked up, you shouldn’t notice any difference in resistance due to brake bias unless you’re pressing the pedal - brakes off is brakes off, unless something’s spectacularly out of adjustment!

sounds like a bit of low-usage stickiness to me. As Barry has said the piston might well stick again. Use it as your family daily driver for 6 months and that should sort it. 

The Cobra Register - Historian
Several old bangers, which used to include a 289
fbhvc.co.uk
thesahb.com


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Clive Johnston
(@clivew)
Active Member
Joined: 6 years ago
Posts: 19
 

If it is the Hawk pedals, the pivot spindle can get rusty if it gets wet causing the brake pedal to stick and not return properly. I had this problem a good few years ago and the only way to sort it without removing the pedal, is by working it off and on at the same time as dripping some oil on the shaft. A better idea would be to fit a grease nipple on the pedal above the shaft.


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David Beck
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Joined: 7 years ago
Posts: 102
Topic starter  

Thanks all, it may well have been a combination of things, the pivot spindle does need removing and cleaning which should prove an interesting challenge

I had forgotten the 2 inches of water that accumulated in the foot well at Le Mans last year! It has been lubricated to death and will try the tip from Clive.

I also stripped down the front calipers and removed all the sticky copper slip/grease/dirt combo on the back of the pads which was not helping release the pistons. At the MOT today the guy was really helpful and helped check the pads in the rears which seemed loose and we could move the pistons as well so they look all good.

Brake pressures were good and even and it sailed through so I will get through the weekend and see where we are, I suspect it is part down to previous limited use, we have added almost 6000 miles in two years compared to the 8000 in the previous decade or so!

Thanks all.

 

The Cobra Register - Founder Member


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