[akshay4587]

Originally Posted by Red Liner

If the brake pedal judders (mimicking you pumping the brakes manually) when you stand on them, then your ABS is kicking in. The lights will not come on. The ABS should not allow the wheels to lock. If it does, then you have a problem.

I have felt the judder from the pedal at times.
and i have heard a protest or two from tyres too,once or twice may be.
will check again,and revert.
How about trying on a dirt track\gravel?

[Sutripta]

Originally Posted by SPIKE ARRESTOR

@SS da, Yes, there are differences.

And what are the differences? Intrigued.

Regards
Sutripta

[SPIKE ARRESTOR]

^^ Rear brake liner geometry (included angle / start angle of liner), length of shoes, LSPV cut off pressure, liner material to mention a few. Forgot to mention even the wheel cylinders were different.

Spike

[Sutripta]

^^^
No, differences between the cylinders. Esp dia and travel.

Regards
Sutripta

[Red Liner]

Originally Posted by akshay4587

I have felt the judder from the pedal at times.
and i have heard a protest or two from tyres too,once or twice may be.
will check again,and revert.
How about trying on a dirt track\gravel?

I dont think you would be traveling at 100 kmph on a dirt track. I think you would do this on a highway, and you want the ABS to kick in and help you brake safely ahead of an errant trucker or a flitting bike rider.

[hvkumar]

Originally Posted by hvkumar

Further updates on the braking problem:

- The brake calipers were removed, and the rubber kit changed. The rubbers looked absolutely fatigued and definitely did not have any rubbery action left. Looks like the dead rubbers were preventing the brake piston from retracting after every braking action, causing the jam. Hopefully, the change will solve my problem

- the brake pads were totally worn out - in some 20,000 odd kms or so, must be because of the jamming that must have kept the brake pads in the disc longer than required. They have been changed.

- the rear brake shoes were totally worn out, especially on the left hand side. They are probably less than 40,000 odd kms old. Both the brake cylinders were OK, since I had changed the RHS cylinder last time I had changed the brake shoes.

- BUT, here is the shocker: the brake cylinder on the LHS was not the correct one! It was that for the crde Scorpio, which apparently has double the braking action than my non-crde Scorpio. This had been changed by my ASC some 1 year ago. What is the impact? The more powerful LHS brake cylinder was applying stronger braking action, resulting in wearing out the brake shoes in LHS. The brake shoes had completely worn out the brake drums - it was also completely uneven and wavy in one section! Maybe this was also causing the inefficient braking and jamming.

- It looks like it will be impossible to do the facing of the brake drum since it may cause it to become too thin, so I am going to change both the brake drums. And the brake shoes of course. Moreover, I am now trying to get the real brake cylinder (not in stock) to replace the wrong brake cylinder.

Now you also know how bad ASCs can cause so much of damage to Scorpios. Not only have the jokers not replaced the brake caliper rubbers for such a long time, but they have also put the wrong part.

Net result, the Scorpio is grounded for the next 24 hours awaiting parts.

So where are we now on my braking problem?

- Changed brake pads
- Changed brake shoes
- Changed wheel caliper rubbers
- Replaced the wrong rear LHS rear cylinder kit (now I have my non-crde cylinder instead of the wrong crde one which was wrongly fitted by the ASC)
- bled brake oil
- topped up on brake oil

But....

- the new brake drum refused to fit, there was too little gap between the new brake shoes and the brake drum walls. The crde brake drum was also tried out, but that has a broader angle in the inner radius and will not fit with my non-crde brake shoes. So we have to make do with the old brake drum itself, except that the LHS brake drum (which had the wrong cylinder and had worn out unevenly) is now interchanged with the RHS. We have thinking of facing the new brake drum a little and try to refit it later today or tomorrow.

- the hand brake setting is now gone kaput thanks to the new brake shoe and despite recalibrating it, it has not worked and the cable appears to have got dislodged, and we may change the cable too.

Test run yesterday night was a flop show.
Today morning's regular 41-km commute to office was a nightmare!
Test of brake booster was OK too.

But....
I press the brake pedal, I feel a little bite in the top end, but then the brake sinks in too easily - like a sponge - and bites at the very bottom end, so that car comes to a halt with a screech abruptly. Release the pedal and it retracts without any trouble. If immediately apply (meaning I do 2-3 rapid brake pedalling in under 5 seconds) the second or third time, braking is better. But do it one more time and brake pedal becomes hard and braking action ceases.

Looks like I am back to square one after having spent quite a packet to resolve the 2 pending issues - worn out/ ineffective rubbers in brake calipers and problematic rear brake cylinder.

That leaves the replacement of the brake drum - did not work out thanks to the misfit - which means the unevenness in the (old) LHS/(new)RHS brake drum may be jamming the brakes again.

I tried one other thing midway. The brake oil is overflowing a little from the cap of the brake oil tank thanks to all the topping up. So I opened it, refitted the cap, and also increased tyre pressure to 32 psi (from my normal 31 psi). I think there is a little improvement in braking and the pedal action seems to be marginally better.

There was a theory I heard about the possibility of a choked air hole in the brake oil tank cap that can cause problems - is that something to worry about? The brake oil tank cap needs to be changed?

I am now jittery, looking at the GM-Car-Start-Ice Cream solutions!

My BP has risen significantly in the last few weeks and if you find me in hospital, don;t be surprised. I have even seriously started thinking of scrapping this car if a solution cannot be found. With ASCs who are both irresponsible and incompetent, I am not sure if one can recommend a M&M car any more.

[SS-Traveller]

Originally Posted by hvkumar

- the new brake drum refused to fit...

That is strange. New shoes, new wheel cylinders and new drums, all meant for the same car, but the drums refused to fit?

- the hand brake setting is now gone kaput thanks to the new brake shoe

The least of our problems - can be taken care of once the rest of it works smoothly.

I press the brake pedal, I feel a little bite in the top end, but then the brake sinks in too easily - like a sponge - and bites at the very bottom end, so that car comes to a halt with a screech abruptly. Release the pedal and it retracts without any trouble. If immediately apply (meaning I do 2-3 rapid brake pedalling in under 5 seconds) the second or third time, braking is better. But do it one more time and brake pedal becomes hard and braking action ceases.

Air in the system, IMO. Bleeding required one more time, all 4 wheels.

...the cap of the brake oil tank... I opened it, refitted the cap, and also increased tyre pressure to 32 psi (from my normal 31 psi). I think there is a little improvement in braking and the pedal action seems to be marginally better.

There was a theory I heard about the possibility of a choked air hole in the brake oil tank cap that can cause problems - is that something to worry about? The brake oil tank cap needs to be changed?

Reducing tyre pressure by 1 psi won't make any difference to braking, but the vent hole of the brake MC cap being jammed MAY make a difference - but then, never seen a jammed vent hole cause so much loss of braking.

My BP has risen significantly in the last few weeks and if you find me in hospital, don;t be surprised. I have even seriously started thinking of scrapping this car if a solution cannot be found. With ASCs who are both irresponsible and incompetent, I am not sure if one can recommend a M&M car any more.

Is someone in M&M reading this? And what concrete and constructive steps are being taken to address this? I feel the issue at hand is more about poor diagnosis, incompatible parts and incompetent repair all coming together, rather than some complicated issue that is seriously expensive to fix and/or needs special tools/skills to carry out.

[hvkumar]

Originally Posted by SS-Traveller

That is strange. New shoes, new wheel cylinders and new drums, all meant for the same car, but the drums refused to fit?

That is the problem with old cars - everything is worn down, things don't fit well any more. Some facing will have to be done in the brake drum before it can be fitted. That is the stage I am on.

The least of our problems - can be taken care of once the rest of it works smoothly.

Air in the system, IMO. Bleeding required one more time, all 4 wheels.

Done 3 times yesterday alone.

Reducing tyre pressure by 1 psi won't make any difference to braking, but the vent hole of the brake MC cap being jammed MAY make a difference - but then, never seen a jammed vent hole cause so much loss of braking.

That is something I will check out later today just before I leave my office, hoping my brakes will work better thereafter on way back home.

Is someone in M&M reading this? And what concrete and constructive steps are being taken to address this? I feel the issue at hand is more about poor diagnosis, incompatible parts and incompetent repair all coming together, rather than some complicated issue that is seriously expensive to fix and/or needs special tools/skills to carry out.

Imagine, I was there when they changed the rear cylinder, but how does one find out that the buffoons in the ASC did this? I am sure that they knew what they were doing, when the right part is not available, fit whatever part is available, who cares for the consequences? The rear cylinders look the same from outside but the part number is different, the ASC knew exactly that my car was non-crde, there was no way he could have made a mistake. My earlier experiences with this "best" ASC have been terrible - they recamber leaf springs and put it back without the bush leading to 5 leaves breaking simultaneously, or they take off the restraining bolts for the accelerator wire letting it grate against the engine block and break up inside leading to accelerator jams, etc. I have been to the so-called company ASC - which is the worst, worse than the worst ASC - and I have found their workmanship the worst and to top it all, they stole the jack from my car. So there is no point in wasting time with a company like M&M, I have done all that before (once upon a time, I thought this great Indian company would be more responsive to customers), it is only a waste of time.

Anyway, my mechanic is sure that the unevenness in the brake drum is causing the problem and I am still hopeful that this solution will be found.

To be an ASC of M&M is heavenly, I guess.

[Sutripta]

Originally Posted by hvkumar

- the new brake drum refused to fit, there was too little gap between the new brake shoes and the brake drum walls.

Originally Posted by hvkumar

Some facing will have to be done in the brake drum before it can be fitted.

Brake linings might be oversize. Drum might be out of specs. But don't true a new drum, ask for a replacement. In the meantime measure everything.

Regards
Sutripta

[hvkumar]

Originally Posted by Sutripta

Brake linings might be oversize. Drum might be out of specs. But don't true a new drum, ask for a replacement. In the meantime measure everything.

Regards
Sutripta

I have already bought the brake drum, and it is the one meant for my Scorpio. We measured it against the existing one and it matches. Therefore, I have no choice but to have it faced so that we can try fitting it.

BTW, am not doing this in the ASC. It has been quite a task to procure the brake drums because these are not available easily anymore like most of the parts of the older Scorpios.

I was talking to kaiserkektar - he had an identical problem sometime ago when he was driving to Udaipur. It was solved by changing the Brake Booster & Master cylinder (and the ASC there sold him the last one in his stock and told him he was very lucky!). I am now bewildered - when my brake booster had failed, I had different symptoms. Besides, when I do the classic test to validate the booster's efficient performance, I did not face any problem.

[getsurya]

HVK,

Feel sorry for what you are going through with a ride you have owned so long! I wish M&M reads this and does something to make the right parts available to you at the earliest.

The kind of maintenance rigor you employ- M&M should be eager to assist you!

[hvkumar]

Originally Posted by getsurya

HVK,

Feel sorry for what you are going through with a ride you have owned so long! I wish M&M reads this and does something to make the right parts available to you at the earliest.

The kind of maintenance rigor you employ- M&M should be eager to assist you!

Thanks, getsurya. The unfortunate thing is that M&M ASCs are terrible and the caucus ensures that parts are also not available in the market.

[Sutripta]

Hi,
When you had first described your symptoms, I thought culprit is the servo if the other simpler stuff checks out OK. Still think so.


However

Originally Posted by hvkumar

I press the brake pedal, I feel a little bite in the top end, but then the brake sinks in too easily - like a sponge - and bites at the very bottom end, so that car comes to a halt with a screech abruptly. Release the pedal and it retracts without any trouble. If immediately apply (meaning I do 2-3 rapid brake pedalling in under 5 seconds) the second or third time, braking is better. But do it one more time and brake pedal becomes hard and braking action ceases.

This normally means either a master cylinder fault, or that one of the circuits is not working, either because it is leaking, has lots of air, or is very badly adjusted.

If you tie this in with overflowing of the resrvoir, to my mind it seems that something is forcing your disk pads apart. Pads normally always just touch the disk. Which is why no adjustment is necessary. If the pads are forced apart even slightly, it will displace a lot of fluid. (resulting in the overflow) and will need a lot of pedal travel (or pumping) to recover that lost ground. So please check for warped disks, bad wheel bearings. What is the brake pedal feel like if the car is stationary?

I must add that I am unable to account for the part marked out in bold.

Regards
Sutripta

[SPIKE ARRESTOR]

Originally Posted by Sutripta

Hi,
When you had first described your symptoms, I thought culprit is the servo if the other simpler stuff checks out OK. Still think so.

This normally means either a master cylinder fault, or that one of the circuits is not working, either because it is leaking, has lots of air, or is very badly adjusted.

Didn't understand above statement in bold. Dada, any specific reasons for zeroing on the servo? Anything specific to the ports?

Spike

[Sutripta]

^^^
Hi,
Applies to drums, not disks. If the shoes have a huge distance to travel, it will use up almost all the displacement of the master cylinder.

What do you think of the rest of my reasoning?

Regards
Sutripta