Donations towards server fund so far this month.

 
£0.00 / £100.00 per month
Page:
Home > Non-Mini Projects > MGB GT Brakes

gr4h4m

User Avatar

4868 Posts
Member #: 1775
Post Whore

Chester

Hi all, I hope that some of you smart people could help.

I have been getting an old MGB GT v8 on the road, it passed an mot a month or so ago and I have managed 200 miles in it. On the previous post I found a clonk from the diff and I replaced the shims in the diff. In doing that job I had to remove one of the rear back-plates and therefore the rear wheel cylinder. Since this repair the car has pulled to the left if you hit the brakes. Previously I had already replaced the Master cylinder, servo and front brake hoses.

In pursuit of a fix I have since also:

Rebuilt the from callipers (seals and new stainless pistons) as I couldn't get a replacement set. I found a load of rubber gunk in them.
replaced the rear brake hose (there is only one as there is a hard line running along the axel
Replaced both rear wheel cylinder I found some rubber junk in one and the other was weeping

but the car still pulls left quite sharply.

The braking system on the car (from the factory, but it seems strange to me) is connected:
Master Cylinder > Servo (two lines exit the servo)
Servo line 1 > front left calliper
Servo line 2 > T piece >one to the rear axel and both wheels > the other T piece line to the front right calliper

I'm running out of ideas and things to replace. Any ideas? I was thinking of getting another three way connector and bypassing the new servo?



I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


robert

User Avatar

6583 Posts
Member #: 828
Post Whore

uranus

to isolate the problem graham maybe brake on gravel and see which wheels lock up first ?

Bicester scramble ,Medusa enjoyed the trip. https://www.youtube.com/watch?v=Q-7I7-nA19U


Tom Fenton
Site Admin

User Avatar

15243 Posts
Member #: 337
Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

&

TM legend.

Rotherham South Yorkshire

Have you considered changing the front brake flexi hoses? The rubber gunk has got to have come from somewhere, or could be partly blocking a hose?
To determine whats going on its worth running down to your local MOT test station and get them to run it on the brake test rollers and note the readings. At least you know what to aim at then.
I'd also try a pressure bleed in case it is air in the system somewhere.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


gr4h4m

User Avatar

4868 Posts
Member #: 1775
Post Whore

Chester

Thanks both I will try the gravel with the wife driving.
Hi tom I have replaced the front hoses. It was hidden in the text above. I have also been bleeding with an easy bleed.

Iím not sure I understand why the brakes are split the way they are? To me I would think it would make it more sensitive to pulling on the left front? As the line only needs to move the passenger side front pistons where the other line it moving the drivers side front and both rear? I presume itís not as easy as that but it does seem strange.
I will report back

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


Elfturbo

User Avatar

59 Posts
Member #: 2576
Advanced Member

South Staffordshire

Does the MG back brakes have adjusters on them? If they need adjustment up it could result in more fluid displacement to the line which feeds them and the front right calliper, causing the imbalance.

There is not a pressure compensation valve somewhere on the feed to the rear brakes like on the single circuit mini braking system that could be gummed up with old hose?

It will be worth popping to the local friendly MOT garage, they are normally happy to put a car on the brake tester for a 'drink'.

HOSS


gr4h4m

User Avatar

4868 Posts
Member #: 1775
Post Whore

Chester

So I have double checked the rear adjustment and they are both the same.

I had my assistant help bleed the brakes I was checking that the same amount of fluid comes out of the front with one pedal push and it was bang on the same when I marked the test bottle

I also check the front wheel bearings, only having ever done the minis the process is a bit different to say the least. I think they could both do with more shins to get the endfloat but I need to get some shins as they are super small. I re greased them both and ensured they were torqued to at least the minimum to allow the split pin in, but the were both on the minimum. Any more and the bearing got tight let alone had the two thou play, so it looks like more ships are needed and more research from me to check out the procedure.

So I did the gravel check and both front lock up but the left leaves a longer skid in the drive

Still pulls to the left

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


robert

User Avatar

6583 Posts
Member #: 828
Post Whore

uranus

did the backs lock up at all ?

Bicester scramble ,Medusa enjoyed the trip. https://www.youtube.com/watch?v=Q-7I7-nA19U


gr4h4m

User Avatar

4868 Posts
Member #: 1775
Post Whore

Chester

No Robert but maybe I wasnít going fast enough?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


gr4h4m

User Avatar

4868 Posts
Member #: 1775
Post Whore

Chester

tonight I,

I checked the rear hard lines and the all look good and no kinks.
I have replaced the rear shoes. The right rear look much darker in colour than the left and I wonder if they had been contaminated. Plus they must be a good few years old.

I have also swapped out the front hoses for goodridge just incase the new rubber ones were soft. I must admit getting all the air out of the system is a pain with all the high lines, even with the eazibleed I must leave it all now to rest overnight give it one last bleed and road test tomorrow.

There is something funky going on but Iím sure I will find it in the end

Maybe this is the issue. A bent rear shoe


Attachments:

Edited by gr4h4m on 5th Jul, 2019.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


gr4h4m

User Avatar

4868 Posts
Member #: 1775
Post Whore

Chester

Thanks all for the help and motivation, itís fixed, is was the bent rear shoe.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


robert

User Avatar

6583 Posts
Member #: 828
Post Whore

uranus

well done graham , that's an odd one .

Bicester scramble ,Medusa enjoyed the trip. https://www.youtube.com/watch?v=Q-7I7-nA19U


Tom Fenton
Site Admin

User Avatar

15243 Posts
Member #: 337
Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

&

TM legend.

Rotherham South Yorkshire

Well done finding it. Must have been the shoe grabbing the drum early causing the car to pull from the rear brakes. A run on the MOT brake rollers would have helped narrow that down to a rear problem.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


gr4h4m

User Avatar

4868 Posts
Member #: 1775
Post Whore

Chester




On 6th Jul, 2019 Tom Fenton said:
Well done finding it. Must have been the shoe grabbing the drum early causing the car to pull from the rear brakes. A run on the MOT brake rollers would have helped narrow that down to a rear problem.


I agree Tom itís strange that it passed an mot about 4 weeks before. I still donít know what caused the bend. I will put it down the previous owners as the last mot in 2011 showed a failure on front and rear brakes. I also noticed that on of the shoes had picked what looked like rust. I wanted to run the car for a few miles and then change the braking material using the old stuff to clean up the surfaces.
I recon the design makes it sensitive a rear issue effecting the front. Iím still happy as now it has a week serviced braking system, that canít be a bad thing.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Home > Non-Mini Projects > MGB GT Brakes
Users viewing this thread: none. (+ 1 Guests)  
To post messages you must be logged in!
Username: Password:
Page: