Brake Upgrade Options & Ideas

[kevin the chicken]

Sounds like you just need to go through the whole system and make sure it's all up to scratch. I did with mine because it had a fluid leak from the front. I used new seals and pistons, pads and shoes. I made sure it was bled properly. Small children are a useful special tool here when bleeding. Mine stops very well and I am not tempted to mess around with it. If yours still won't lock up then it is time to look at how the system is set up and work out what is wrong before spending hundreds of pounds on kit which may still not cure the issue or may only mask it. Front pistons and seals were only about forty quid when I did them.

[Guest Ian & Carole]

Our car started off with 9 " drums and 240 mm vented discs.

 

When I removed the servo to get the 4AGE engine in I upgraded the front to 265 mm vented discs and calipers.

 

The bigger calipers bolted straight on to original hubs and that was enough to stop the car.

 

Never up-rated pads just kept them clean and glaze free.

[brumster]

Firstly, don't relate brake size to BHP. The two are not directly related. More BHP just means you can get up to higher speeds quicker, which means you're then having to brake harder, but the work the brakes have to do is not just a factor of speed - it's weight too. And thankfully our cars are not the heaviest around. So if you're tracking or racing the car up to speeds well in excess of the legal limit, then absolutely, you want to uprate the brakes... but for most road cars, provided they have the ability to lock the tyres if pressed too hard, you should have all the braking ability you need. Obviously you want a margin of error in there, you don't want this all happening at the extremes of your pedal travel, but... you get my point

 

Dino, what are the M/C sizes (should be stamped on the side of the castings, 6.25 or so) ?

Given the master and slave cylinder sizes you should be able to work out the ratio operating on the front and back, but it will most likely be a bit of trial and error in finding what works best for you. If you've got a very firm pedal, I would go down a size on the front master cylinder to try and bring the pressure up on the front, at the sacrifice of some pedal travel - but this is a good thing, as you'll require less effort to depress. Think of the master cylinder as a nail you're pushing into a cork board... going down in size makes it more like a pin, meaning you can push it in a lot easier

 

To put this all into context, the standard Grp A PTS spec rally brakes on 205's in the 90's was 260mm Alcons, to stop about 900Kg of Peugeot 205 repeatedly on a rally stage, and you didn't hear Richard Burns whinging that the brakes weren't good enough... so I strongly think the standard Sierra brakes on a similarly-weighted (maybe slightly lighter) 7esque car should be more than up to the job . I know many guys who still rally their 205's on standard discs and calipers because of the reduced unsprung weight.

 

You've also got the delights of the balance bar to faff around with, these can be a pig to get working properly if you don't get them set up as per spec. They are quite sensitive to spacing between the knuckles and the central bearing and can bind on the edge of the pedals and so forth.

[brumster]

Oh, one more point, from experience - not saying this is your problem but - there was a plethora of cheap Girling-copy master cylinders kicking about for quite some time, and the market was flooded with *bleep*ty-quality Girling M/Cs that really are not up to the job... the bores were crappy and I think this resulted in premature seal failure. It sounds to me like your tester has identified it's the slave cylinders at the back, which is great, but I just mention it for future reference in the thread. When I see those £10 "Girling" M/Cs on eBay, I do start to tremble somewhat

Edited June 14, 2016 by brumster

[Dean Roberts]

Hmmm....Just had a good read thru the discussion and can definitely confirm that no matter how hard the brake are jumped on - none of the brakes will not lock up (maybe a good thing).

But on the flip side they also take an age to slow the vehicle (mainly the front disks doing all the work)

 

According to the rollers on the MOT centre, the tiny front disks barely passed and the rear drums were non existent.

I removed the drivers side drum last night and found a leaking cylinder and hoping that this maybe be the issue.

Tonight I will have a look at the passenger side drum and give a little more feedback on some of the questions being asked.

 

Highly appreciate the feedback.

 

 

 

So it looks like the consensus is to fix what is broken and get it working properly now, then maybe look into upgrading to something cheap, reliable and better once the problem has been resolved.

Damn you BRUM - I was about to order 2x of those £10 slave cylinders off a famous auction site.......

Edited June 14, 2016 by Dino

[brumster]

So the back shoes are most likely contaminated, so that's fine, that explains the failure at the back. So you might as well do that leaking cylinder, for sure. I doubt bigger back brakes are going to improve things so it's not money wasted.

On the fronts, I'd take the pads out and check them for glazing, check the disk thickness, maybe push some fluid through the front circuit and see if things improve. What are they, 240's? Vented or solid?

 

Find out that m/c size too. That might be the easiest fix.

[Dean Roberts]

this might help

http://www.ebay.co.uk/itm/Boat-anchor-naval-folding-admiralty-style-23-5-kg-81-cm-FREE-POSTAGE-/231975969683?hash=item3602d86393:g:NLkAAOSwmtJXXAFD

 

Nutta

[Longboarder]

I am guessing you have a bias bar with the pictured setup. I'm also guessing that you have .625 m/c for the fronts and .75 for the rears. If that is so you need to check the bias bar is able to operate properly. At rest it should be fully angled, the side that pushes the front brake back toward your feet. There must also be enough play between the two adjustable yokes to allow the bar to fully pivot. This is because the piston operating the fronts moves about an inch while the piston operating the rears moves about 1/4 inch. This requires a big swing on the bias bar.

Common mistakes in setting up is to set the bar at right angles to the pistons or not allow sufficient play between the yokes to allow full swing. Result is the bar swings as much as it can, locks and stops when the rears are solid. No more pressure is then possible to send to the fronts which are only half on.

So check the setup please.

I would still go for m1144 compound all round.

 

Nigel

[agent_zed]

how well did the handbrake fair on the rollers? seeing as they use the same shoes as the footbrake. I assume it was also rubbish if the shoes are contaminated but if for some reason the handbrake was fine and the footbrake was not, it will tell you the drums are fine and it's the hydraulics at fault. just a thought.

[Dean Roberts]

how well did the handbrake fair on the rollers? seeing as they use the same shoes as the footbrake. I assume it was also rubbish if the shoes are contaminated but if for some reason the handbrake was fine and the footbrake was not, it will tell you the drums are fine and it's the hydraulics at fault. just a thought.

 

Mmmmmm....trying to remember on the sensor and the figures.

 

Front brakes were reading different values possibly something like -

 

Drivers side 160

Passengers 130

 

Rears Brakes:

 

Never got over 50 and I do remember them laughing and the tester saying the handbrake was also rubbish.

 

I will try cleaning up the rear drums and replacing the slave cylinders (especially if they are leaking), bleeding and double checking the bias bar set-up.

Then back around to the rollers to see if this improves things.

 

 

BRUM - Any way of identifying the duff slave cylinders from the good?

[Guest 2b cruising]

this might help

http://www.ebay.co.uk/itm/Boat-anchor-naval-folding-admiralty-style-23-5-kg-81-cm-FREE-POSTAGE-/231975969683?hash=item3602d86393:g:NLkAAOSwmtJXXAFD

I don't just like it, I love it.

[Dean Roberts]

Our car started off with 9 " drums and 240 mm vented discs.

 

When I removed the servo to get the 4AGE engine in I upgraded the front to 265 mm vented discs and calipers.

 

The bigger calipers bolted straight on to original hubs and that was enough to stop the car.

 

Never up-rated pads just kept them clean and glaze free.

 

Ian, were they off a Ford Granada or XR4?

Edited June 14, 2016 by Dino

[Guest Ian & Carole]

 

Ian, were they off a Ford Granada or XR4?

IIRC they were still Sierra so i would assume XR4

 

Have a look through this it might help with your research.

 

 

http://www.biggred.co.uk/brake-calipers?specs=91

[Bob Tucker]

+1 for Mintex 1144 pads which I have been using for many years.

They work instantly on the road, do not need heating up, but will not fade

on the trackdays I have done, whereas standard pads work fine on the road but do fade pretty

quickly on track.

My brake setup is standard 2.0 front (everything), M1144 pads, Rally design tandem M/C, no servo.

Rally design said that it wouldnt work, but i bought the 6:1 brake pedal, & although it does take some pushing,

it can still lock up Toyo 888s.

Just had it MOTd & the front wheels registered 195, & 200.

[Dean Roberts]

Just got to get into wet leaking garage and can confirm....

 

Flood lights don't work.

Floor is wet.

Roof is leaking...

 

But more importantly the cars are OK

 

Master cylinders are as follows:

 

Front - 0.625

Rear - 0.7

 

Front brakes are 240mm vented disks

Rear are smaller 1.6 drums with slave cylinder leaking and very, very dirty yet the spring and shoes look very good (after cleaning).

Dave informs me all the brakes are good to go and the shoes etc. were updated in 2013.

 

So it looks like I need to replace smaller, tired worn out drums and cylinders before moving forward.

Luckily as per Ian's suggestion I already have a donor car onsite for testing