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Gritty Brake Pedal?
MakeEverything - 30/4/11 at 04:16 PM

Hi All,

My car has been standing for a year or so, and ive been doing the brakes. I had a problem with a gritty and very stiff pedal, so started to rebuild the calipers. Ive done one (which was squeaking before) but still have a horrible feel on the pedal. Could this be the master / servo?

Thoughts / questions please.

jacko - 30/4/11 at 04:23 PM

What do you mean by Gritty

MakeEverything - 30/4/11 at 04:27 PM

Its like pushing my foot into a bucket of stones. and i have to pull the pedal back for half of the travel with my foot.

marcjagman - 30/4/11 at 04:29 PM

Bleed all the brakes, if that doesn't work then master cylinder could be FUBAR

jacko - 30/4/11 at 04:30 PM

Could it be the bearings in the pedal ?if not i would say m /cylinder seals sticking

MakeEverything - 30/4/11 at 04:35 PM

OK, thanks. Ill get the master cylinder out for a check. What about the servo?

austin man - 30/4/11 at 04:35 PM

remove the pushrod and clean it may be a little rusty and binding. We has a similar problem on an Indy it wa due to the angle and thickness of the rod, trimmed it down and Voila no problems now. The ros was catching inside the cylinder

[Edited on 30/4/11 by austin man]

blakep82 - 30/4/11 at 04:37 PM

check the pivot too.
might be a pivot bolt you forgot to grease?

MakeEverything - 30/4/11 at 05:03 PM

quote:
Originally posted by blakep82
check the pivot too.
might be a pivot bolt you forgot to grease?


You mean Clevis?

blakep82 - 30/4/11 at 06:47 PM

quote:
Originally posted by MakeEverything
quote:
Originally posted by blakep82
check the pivot too.
might be a pivot bolt you forgot to grease?


You mean Clevis?


nope the pivot. clevis joins your pedal to the master cylinder push rod, but either above or below that, you have to pivot the pedal somewhere! usually a bolt.

MakeEverything - 30/4/11 at 07:36 PM

quote:
Originally posted by blakep82
quote:
Originally posted by MakeEverything
quote:
Originally posted by blakep82
check the pivot too.
might be a pivot bolt you forgot to grease?


You mean Clevis?


nope the pivot. clevis joins your pedal to the master cylinder push rod, but either above or below that, you have to pivot the pedal somewhere! usually a bolt.


Nope, i have push / pull cables doing the job and clevises both ends.

Ive fitted the calipers back on and tried the handbrake, but the handbrake doesnt seem to operate the piston?? When trying to get the cable off the other day, i rotated the mechanism - is it possible to rotate this too far to break it?
Getting a bit pissed off with brakes now!!

blakep82 - 30/4/11 at 07:48 PM

push pull cables on your brake pedal? eh? i'm lost now. you said you had problems with the pedal first of all!

MakeEverything - 30/4/11 at 07:55 PM

quote:
Originally posted by blakep82
push pull cables on your brake pedal? eh? i'm lost now. you said you had problems with the pedal first of all!


The pedal is connected to a push pull cable, which operates the servo. The servo is mounted under the bonnet (mid engined car) laterally, so needs to operate through 90 degrees. Both ends have clevis pins holding the cable on, and the outer is mounted at both ends, to fixed points.

I still have problems with the pedal, but have discovered that the handbrake doesnt work.

blakep82 - 30/4/11 at 08:11 PM

and how does your pedal work without some kind of pivot point? lol



is you cable nice a free to move? lubricated etc

[Edited on 30/4/11 by blakep82]

britishtrident - 30/4/11 at 08:25 PM

The idea of depending on cable to operate the service brake send shivers down my spine.

MakeEverything - 30/4/11 at 08:36 PM

quote:
Originally posted by blakep82
and how does your pedal work without some kind of pivot point? lol



is you cable nice a free to move? lubricated etc

[Edited on 30/4/11 by blakep82]


Muppet. The rod is connected BELOW the pivot!! lol

Trident, its a push / pull cable, not like a handbrake cable.

ETA: and the pedals are floor mounted, which means its the same as your diagram blake, but upside down.

[Edited on 30-4-11 by MakeEverything]

daviep - 30/4/11 at 09:13 PM

My fiver would be on that the cable is not sliding freely, they don't like being bent too tightly, they also don't like water very much.

Common name for a push/pull cable is a "bowden cable" they are used extensively on plant and machinery and aren't particularly strong or reliable. Remember that if you are using the cablein the push mode then it will only be as strong as the anchors on the outer of the cable.

Like BT I wouldn't be happy with a cable operating my brakes,is it not possible to use rods and bell cranks?

Davie

[Edited on 30/4/11 by daviep]

MakeEverything - 30/4/11 at 10:34 PM

quote:
Originally posted by daviep
My fiver would be on that the cable is not sliding freely, they don't like being bent too tightly, they also don't like water very much.

Common name for a push/pull cable is a "bowden cable" they are used extensively on plant and machinery and aren't particularly strong or reliable. Remember that if you are using the cablein the push mode then it will only be as strong as the anchors on the outer of the cable.

Like BT I wouldn't be happy with a cable operating my brakes,is it not possible to use rods and bell cranks?

Davie

[Edited on 30/4/11 by daviep]


Ill have a look at the cable when i take it all apart. I might look to replace the master and ditch the servo altogether. Just means ill need to rethink the master. This would allow it to be mounted on the bulkhead with a remote reservoir. Its all stuff im going to look into tomorrow.

Mr Whippy - 1/5/11 at 03:03 AM

low mounted master cylinders are bad for getting grit in them, you can get rubber boots to go over the end that still allow the pushrod to go through, classic vw's like the beetle use them and they fit most production car ones too

scudderfish - 1/5/11 at 07:58 AM

Ditch the servo unless you are too delicate to stomp on the pedal.

MakeEverything - 1/5/11 at 09:01 AM

quote:
Originally posted by scudderfish
Ditch the servo unless you are too delicate to stomp on the pedal.


britishtrident - 1/5/11 at 10:10 AM

Rover 75 uses a BMW imposed brake servo layout with a neat bell crank connected to the pedal to allow the master cylinder and servo to sit transversely.


When Lancia brought out the mid engined "Lancia Beta Montecarlo" they got a lot of complaints about premature front wheel locking, the second series cars known as the "Lancia Montecarlo" cured this by simply deleting the servo.