S1 brake pedal to the floor
Discussion
Finished reinstalling rear drums and bleeding the system-all four wheels-using a pressure bleeder. New wheel cylinders installed. Front brakes are working fine but the rear drums appear to have an issue.
With the engine running and up on the lift, I engaged first to get the rear wheels moving and then hit the brakes. My wife observed the rear wheels stopped. But with the engine off, hitting the brakes did not have any impact on the rear brakes. After pulling the drums off again, I notice no movement in the new wheel cylinders when I pressed the brakes with engine off. Front brakes engage with the engine off however.
I suspect the adjusters are not working properly although I think I reinstalled them as they were. Would adjustors not working cause the pedal to go to the floor? I set them so that the drums required some effort to get over over the brakes shoes. But although I can feel more resistance in the pedal, it still goes to the floor. I tried pumping the brakes about 50 times but no difference ... still to the floor.
The brakes did work fine before I disassembled everything for repainting etc.
Emergency brake also isn't engaging.
Any thoughts?
With the engine running and up on the lift, I engaged first to get the rear wheels moving and then hit the brakes. My wife observed the rear wheels stopped. But with the engine off, hitting the brakes did not have any impact on the rear brakes. After pulling the drums off again, I notice no movement in the new wheel cylinders when I pressed the brakes with engine off. Front brakes engage with the engine off however.
I suspect the adjusters are not working properly although I think I reinstalled them as they were. Would adjustors not working cause the pedal to go to the floor? I set them so that the drums required some effort to get over over the brakes shoes. But although I can feel more resistance in the pedal, it still goes to the floor. I tried pumping the brakes about 50 times but no difference ... still to the floor.
The brakes did work fine before I disassembled everything for repainting etc.
Emergency brake also isn't engaging.
Any thoughts?
Edited by robinlarry on Tuesday 5th May 04:24
Edited by robinlarry on Tuesday 5th May 05:09
so the handbrake doesn't work either? Kind of rules out a hydraulic problem (although you might have two different problems, right enough)
When you bled the brakes, you did get fluid through the system? No blockages in the pipes?
I think (and its a bit of a guess since i can't see the car) that you need to check the handbrake. It's the handbrake that works the self-adjuster mechanism, so the shoes might be too far from the drums. When you press the brakes, the displaced fluid moves the pistons, but not enough for the shoes to contact the drum.
When you apply the handbrake, does it stop at 3 or 4 clicks of the lever? Do the levers at the shoes move? I would check that first.
If you move the shoes apart manually, does the self-adjuster pawl move to take up the extra travel? Make sure it's not sticking - and that it doesn't "fly off" again when you let go and it's back under spring tension (if the teeth on the pawl or the fixed toothed wheel are worn).
When you bled the brakes, you did get fluid through the system? No blockages in the pipes?
I think (and its a bit of a guess since i can't see the car) that you need to check the handbrake. It's the handbrake that works the self-adjuster mechanism, so the shoes might be too far from the drums. When you press the brakes, the displaced fluid moves the pistons, but not enough for the shoes to contact the drum.
When you apply the handbrake, does it stop at 3 or 4 clicks of the lever? Do the levers at the shoes move? I would check that first.
If you move the shoes apart manually, does the self-adjuster pawl move to take up the extra travel? Make sure it's not sticking - and that it doesn't "fly off" again when you let go and it's back under spring tension (if the teeth on the pawl or the fixed toothed wheel are worn).
robinlarry said:
Any thoughts?
Take it all apart and start again. Loads of information, diagrams etc. available on line, including this clicky and more clicky.If that don't work, this is your brakes we're talking about, reasonably important, maybe time to seek professional advice? Someone with experience, looking at it in the flesh so to speak will probably spot the error straight away
I don't believe it's a hydraulic issue since I bled the rears twice and fluid came through without any air bubbles.
When I had my wife pull the handbrake, the adjustors on both side moved ... but the horizontal plate - self-adjusting strut, slid with the shoes, since they were not confined by the drum. I'll reinstall drums and try pulling the emergency brake a few times to see if that resolves the problem.
If not, then the inevitable ... start all over and disassemble.
Would this adjustment issue be the reason the brakes go all the way to the floor? They didn't do that before I tore everything apart and replaced the wheel cylinders.
When I had my wife pull the handbrake, the adjustors on both side moved ... but the horizontal plate - self-adjusting strut, slid with the shoes, since they were not confined by the drum. I'll reinstall drums and try pulling the emergency brake a few times to see if that resolves the problem.
If not, then the inevitable ... start all over and disassemble.
Would this adjustment issue be the reason the brakes go all the way to the floor? They didn't do that before I tore everything apart and replaced the wheel cylinders.
Edited by robinlarry on Tuesday 5th May 15:49
robinlarry said:
I don't believe it's a hydraulic issue since I bled the rears twice and fluid came through without any air bubbles.
When I had my wife pull the handbrake, the adjustors on both side moved ... but the horizontal plate - self-adjusting strut, slid with the shoes, since they were not confined by the drum. I'll reinstall drums and try pulling the emergency brake a few times to see if that resolves the problem.
If not, then the inevitable ... start all over and disassemble.
Would this adjustment issue be the reason the brakes go all the way to the floor? They didn't do that before I tore everything apart and replaced the wheel cylinders.
The handbrake should work on 3 to 4 clicks of the ratchet (with the drums on). You can operate the adjusters by hand bit by bit until you can just get the drums on and then if the handbrake works but is a bit slack pressing the foot brake and then pulling the hand brake should adjust it the last bit. If the foot brake still travels too far then you have most likely still got air in the system. They can be difficult to bleed even with an easy bleed kit; mine certainly was after I re-located the balance valve.When I had my wife pull the handbrake, the adjustors on both side moved ... but the horizontal plate - self-adjusting strut, slid with the shoes, since they were not confined by the drum. I'll reinstall drums and try pulling the emergency brake a few times to see if that resolves the problem.
If not, then the inevitable ... start all over and disassemble.
Would this adjustment issue be the reason the brakes go all the way to the floor? They didn't do that before I tore everything apart and replaced the wheel cylinders.
As the brakes are dual circuit I would not expect the pedal to go all the way to the floor as the fronts should still be working unless there is in fact air still in the system.
robinlarry said:
I'll try bleeding the rears again. The fronts are working fine but now it seems I'm not getting anything happening with the rear wheel cylinders.
You could also try bleeding the pressure regulator, put some rag around it and crack off the top union while someone presses the pedal or with an easy bleed on. Don't forget to tighten it again before releasing the pedal.Pulled the drums and saw the adjusters working when I pressed the brakes... so the wheel cylinders must be moving a small amount. I reset the adjusters all the way in, reinstalled the drums, and pressed the brakes ... I could hear the adjusters working again ... but I could not feel any braking on the rear wheels. Still, my wife said they did stop the wheels when I put the car into gear last night, so something is happening back there. .
So adjusters are working. Wheel cylinders must be working to some small amount.
I tightened the cable for the Emergency brake. I left it slightly loose so when it's on, with a lot of effort, I can turn the rear wheels. Takes a lot of effort to get two clicks on the ratchet.
BUT ... nothing at all happening with the rear wheels when I press the brakes. Fronts work fine.
Maybe I should try reinstalling the old wheel cylinders? And rebleed.
So adjusters are working. Wheel cylinders must be working to some small amount.
I tightened the cable for the Emergency brake. I left it slightly loose so when it's on, with a lot of effort, I can turn the rear wheels. Takes a lot of effort to get two clicks on the ratchet.
BUT ... nothing at all happening with the rear wheels when I press the brakes. Fronts work fine.
Maybe I should try reinstalling the old wheel cylinders? And rebleed.
Hi Robin, having a similar problem re handbrake after putting mine back together. I also tested (by hand only though) for braking force at the rear with the engine off. I'd put it down to getting the alignment wrong at the lever end of the cable after the body lift but maybe it's something similar to your problem.
My brakes didn't feel too great at the weekend but I'd put that down to new discs and pads needing bedding in and not being used to driving the car for so many months. Not had a problem stopping though with enough foot pressure and the foot pedal doesn't bottom out.
Having week nights off this week but plan to have a look at what's going on this weekend.
Lawrie
My brakes didn't feel too great at the weekend but I'd put that down to new discs and pads needing bedding in and not being used to driving the car for so many months. Not had a problem stopping though with enough foot pressure and the foot pedal doesn't bottom out.
Having week nights off this week but plan to have a look at what's going on this weekend.
Lawrie
http://www.globalclassiccars.com.au/TVR%20Engine-1...
it is the inclined tube with brake pipes at both ends on top of the drivers footwell
it is the inclined tube with brake pipes at both ends on top of the drivers footwell
I hooked up the pressure bleeder and bled the pressure regulator. Some air did escape-I think. When I tried the brakes, they were firm! But when I disconnected the pressure bleeder, the pedal went to the floor. Hooked up bleeder; brakes firm. Disconnected...to the floor.
So if I don't want to drive around with a pressure bleeder hooked to the brake reservoir .... ?
I expect nest step is to inspect seals in the master cylinder.
Cast in P/N on mine is 74660294 0 341 8. We'll see what's inside. The reservoir looks pretty new so I expect it's been rebuilt at some point.
So if I don't want to drive around with a pressure bleeder hooked to the brake reservoir .... ?
I expect nest step is to inspect seals in the master cylinder.
Cast in P/N on mine is 74660294 0 341 8. We'll see what's inside. The reservoir looks pretty new so I expect it's been rebuilt at some point.
Edited by robinlarry on Wednesday 6th May 04:05
daft question - did you change the master cylinder? I'm wondering if the bore is too small and its not displacing enough fluid.
More likely, from your description, is that the pressure bleeder has displaced a seal in the master cylinder so that it's not compressing the fluid when you press the pedal.
All these pressure bleeder, vacuum bleeder gadgets etc are great, but I have had problems with all of them at one point or another, and for me, unless the manual says otherwise, the best way to bleed brakes is the old "crack the nipple / pump the pedal" technique.
More likely, from your description, is that the pressure bleeder has displaced a seal in the master cylinder so that it's not compressing the fluid when you press the pedal.
All these pressure bleeder, vacuum bleeder gadgets etc are great, but I have had problems with all of them at one point or another, and for me, unless the manual says otherwise, the best way to bleed brakes is the old "crack the nipple / pump the pedal" technique.
daft question - did you change the master cylinder? I'm wondering if the bore is too small and its not displacing enough fluid.
More likely, from your description, is that the pressure bleeder has displaced a seal in the master cylinder so that it's not compressing the fluid when you press the pedal.
All these pressure bleeder, vacuum bleeder gadgets etc are great, but I have had problems with all of them at one point or another, and for me, unless the manual says otherwise, the best way to bleed brakes is the old "crack the nipple / pump the pedal" technique.
More likely, from your description, is that the pressure bleeder has displaced a seal in the master cylinder so that it's not compressing the fluid when you press the pedal.
All these pressure bleeder, vacuum bleeder gadgets etc are great, but I have had problems with all of them at one point or another, and for me, unless the manual says otherwise, the best way to bleed brakes is the old "crack the nipple / pump the pedal" technique.
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