GTR Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter #1
Hopefully someone can help me out with my r33.I do not use it much and its probably been used twice the last month.Before that i may use it once every two weeks.I had it booked in for a service so took it to work this morning
On the M25 (someone may have seen me in the hard shoulder)and i noticed the car being very sluggish.Immediately i knew it was a brake problem.
I pulled into the hard shoulder as soon as possible and there was smoke coming from both rear wheels.Sure enough both rear brake disks and calipers were red hot to the extent the calipers are now brown instead of red.
The pads were stuck to the disks. Hope i haven't fried the calipers and disks now. I wait an hour for a recovery truck by which time calipers have cooled down and released so i opt to drive home using handbrake instead of putting it on the pick up truck.it was too low to go on the truck anyhow.
I don't expect its the pistons in the calipers as it would be unusual for both rears to fail at exactly the same time.would i be right in saying this? Maybe i fried them now anyway.Could it be the master cylinder? or blocked brake lines? Does each rear wheel have an independent brake line from the master cylinder or does one line split off in two?anyone know?
I think it maybe that the hydraulic fluid is not being released back after pressure being applied to the brake.After a while maybe it eventually seeps back and the pressure is released.
Would the ABS have anything to do with it?
There is so many components it could be and obviously i would like to pinpoint it before i start getting new everything and for the problem to re occur.Worst thing would be to get new calipers, pads and disks and for them to all lock up again because they were not the problem in the first place.Maybe a flush and new brake fluid will do the job.I just don't want to get stranded again.

Anyone have any ideas before i take it to the garage?
 

·
Registered
Joined
·
3,171 Posts
Could be an ABS unit fault, next time they start to seize on just crack a bleed nipple and see if they immediately release again. "Rubber" brake hoses can break down internally and act as one way valves, it would be highly unlikely both hoses fail simultaneously though!

Brake master cylinders can stop returning if the tiny bleed hole that allows fluid back to the reservoir is blocked with old dirty, debris ridden fluid, but unless you have dual master cylinders it would lock all the brakes on.
 

·
Registered
Joined
·
396 Posts
what rear calipers do you have? I have just had this problem, cracked a disc on a journey so had to buy new ones!! I have the sliding cast iron calipers and the piston sticks. I noticed one side got really hot and had worn out the pads when the other side still had 1/2 left, so I ceaned the piston and bled that side. I then noticed that the other side got hot and the one I cleaned didn't. I cleaned and bled the other side ( bled the whole car) and it was fine for a couple of months of daily use. Then on a longish trip the car suddenly felt sluggish after a big brake and the next time I braked there was a horrible noise from the brakes so I pulled over and found a cracked disc. Put new discs on and cleaned the caliper as best I could until I could push the piston back in with my fingers ( still connected ). The other side was fine, didn't bind the brakes and spun easily. Sorted, two months on and now the side that was fine is starting to stick and get warm ( I check and smell after every trip ( OCD!!!) ) whilst the side I cleaned is fine.
I think it is just the cast iron calipers rusting so I am fighting a losing battle so have just bought some 2 pot sumitomo aluminium ones and will get the discs this month so hopefully that will cure it for once and all. It got me baffled cos I wondered how it could be both sides at more or less the same time but I suppose it makes sense really.
There is one brake line to the rear which the splits to each wheel. The master cylinder has two lines from it, follow them and one goes to the abs unit and then is split to the front from there, the other goes to the abs unit and then on to the rear. Ther are abs sensors on each front and on each of the halfshafts at the rear. From the way it is plumbed in hydraulically I can only assume that the abs unit will release the pressure to the rear line which will let both brakes go at the same time but on the front they will be independant. If it was an abs unit fault then hopefully the light would come on but I thought they failed so that the brakes were just as normal, wouldn't make them stick on.
If you bleed the system and can push the pistons back easily then I think that the pressure release in the master cylinder would be working ok.
 

·
Registered
Joined
·
396 Posts
If yours is a 33gtr then it should have brembos front and rear, so your calipers should be 2 pot aluminium ones so they should be alright. I suppose the pistons could have rusted, don't know what steel they use but you could try cleaning them up as much as you can.
 

·
Registered
Joined
·
5,032 Posts
There's one line going to the back and it splits just before the rear subframe. I say it's dirty brakefluid and it'll always help to clean the calipers and pistons aswell :thumbsup:
 
1 - 5 of 5 Posts
Top