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MG Midget and Sprite Technical - Stainless Steel Brake Lines?

Stainless steel brake lines, are they worth the money?

I finished a complete brake job a couple weeks back on my 1500 (all new parts throughout, including new rubber brake hoses...they came in the kit) & have much better brakes now, but they're still not exactly what I'm looking for.

They just feel a little spongy...so did the old stuff I took off.

I've adjusted & re-adjusted the shoes, bled the system both conventionally & with an Easy Bleeder (twice each by both methods)...no trapped air that I can find.

I'm just wondering if stainless lines would help.

I guess I'm looking for a rock hard pedal, is that even possible with the stock system?

Advice, recommendations, opinions?

Dave




Dave Rhine

If you are referring to the flex lines, they have many fans here. I have not gotten around to installing mine yet, so I cannot speak from experience. OTOH, what brake fluid are you using. I it is the DOT5 silicone fluid, spongy frequently comes with the territory. It is difficult to get all of the tiny bubbles out. Bleed it again in a week.
David "and wash the car to go with all those shiny new parts" Lieb
David Lieb

David

Yes, the flex lines.

I'm using Dot3, after doing a little research on Dot5, I decided Dot3 was best for my application.

You're probably right about driving it around for a little while, the weather on the weekends down here hasn't been that great & I've only put about 30 miles on it since the brake job.

Thanks again for the flange help last summer...it got me started on this never ending journey!

Dave
Dave Rhine

Oh great, now I am an accomplice after the fact ;-)
Glad you are enjoying it!
David "misery loves company" Lieb
David Lieb

Oh yeah Dave, you can get a rock hard pedal on the system, doesn't mean you're going to stop though! ;-) The teflon/stainless flex lines will not swell at all under pressure so might make the pedal feel a bit more firm, but so little I doubt you'd notice unless you're racing. However they are a lifetime investment, you should never have to replace them so I think they're worth the money when starting from scratch. Since you already have new rubber lines then I think I'd wait until you really feel the need for a tiny bit firmer pedal or have a rubber line fail before spending that $65.
Bill Young

The problem may be that I've gotten used to modern braking systems with ABS & power boost!

Until June '09, my last experiences with these little cars were 30+ years ago & my memory may be fogged by the herbal remedies available at that time :)

Just looking to have a bit more confidence when I make another 90+ mph run (haven't seen 100 yet)!

Dave
Dave Rhine ('78 1500)

Dave, I just did the same thing myself, but can't tell you how well it worked 'cause I ran out of brake fluid bleeding them and had to get more. The only thing I worry about is the disclaimer they put in the package - "Don't do this yourself, make sure you have a professional install these brake lines!" Oh well, I guess I will find out soon enough if I got them installed correctly! Because of favorable comments (David Lieb?), I got an Ezibleeder to try and seems to work OK. (you go through a lot of brake fluid, though!) I just have this fear of exploding brake fluid everywhere! David, what pressure do you use?

Cheers,
Jack
Jack Orkin

Dave, I can say that even with stainless flex lines and a perfectly working system you're not going to stand that midget on it's end in a panic stop from 90mph. You'll dip the front down a bit, but I'll bet your butt sucks up more seat cushion than the tires squeel. Remember you're only dealing with a small 9" disc, there just isn't enough leverage on a disc that small to do much braking. Good quality pads will help a lot. Not like a modern car with large discs and power assist. You learn to leave plenty of room between you and the car in front of you and always look for away out on either side. That's not saying the system isn't good though, just different and you will learn to drive accordingly.
Installing premade stainless lines isn't any different from installing the rubber ones so that shouldn't be any problem. Making up your own lines from hose and fittings is a bit of a different matter, but not difficult to do safely. All the lines on my Midget from the brake fail switch block out are stainless flex lines I made up myself. Over 10 years now and no problems at all.
Bill Young

Jack,
I believe you are only supposed to use about 20psi. I generally bleed the pressure of the closest front tire down to that neighborhood and pump it back up afterwards.

Yes, it can use a lot of brake fluid, but think of it as a combined bleed and flush ;-)
David "I bleed easy, too" Lieb
David Lieb

Be VERY careful with braided flexible brake lines on a road car! I have seen a number of failures of both the Goodridge and Earls lines.

The problem seems to be that, unlike a racer with rock hard suspension, a road car will have a (relatively) greater suspension travel which will lead to more flex in the lines, especially in a vehicle that is likely to do a far greater mileage between inspections than a racer. Over time the steel sheath will fatigue and start to break up which can lead to the filaments puncturing the inner teflon tube.

I would ONLY recommend proper 'Aeroquip' hose in -3 size since this is aircraft certificated and seems to withstand flexing better than the cheaper copies. Even then I would be doing regular dye penetrant tests on a yearly basis (when the car is serviced) to check for possible failures.

I don't know about the USA but here in UK the lines come with the warning that they do not conform to the 'Construction and Use' standards for road vehicles. Furthermore, in Europe I understand that the German TUV outlaws their use for this very reason.
Deborah Evans

I wasn't aware of those problems Deborah, nor the lines not meeting road standards. As I said I made up my own set of lines from Aeroquip -4 hose, leaving a good amount of slack in the runs to avoid any sharp bending and so far no sign of any problems. I will monitor them a bit closer now that I'm aware of the problems you mention. I don't put a lot of miles on my car each year, usually less than a couple of thousand each season so even with over 10 years on the road not a lot of mileage. I have to have the car pass a safety inspection every couple of years, much less strict than your MOT, but none of the inspectors has even mentioned the braided lines on the brakes as a problem. Of course each state here has it's own standards so that might be different in another part of the country.


Bill Young

I disagree with Deborah's comments. I've had stainless steel hose on my car's brakes for many years - at least 15. I found that it is possible for a stainless steel line to chafe - it just takes longer than rubber. I've never had a hose fail in the manner Deb describes nor seen one. I have seen a lot of hose damaged by being clamped for brake bleeding purposes - nearly always on racing cars.

The reason some stainless steel brake hose kits are not road legal is simply that they haven't been through a test that certifies them. It's also the case that even if hose was certified and legal for aviation use it wouldn't be street legal unless it had been certified for road use. Not being certified for road use has no bearing on whether or not something is high or low quality.

It's a valid point nonetheless that hose certified for aviation use and Goodridge and other makes can be certified for aviation use, is better than cheap hose and cheap hose is to be avoided.

It's also a valid point that even stainless steel hose doesn't last for either and needs to be checked for damage, wear or deterioration. Given the check Deb recommends appears to be related to usage it might be that depending on the mileage a car covers far longer than 12 months checks would be required - say 3-4 years.

I'd be interested to see a hose failed in the manner Deb describes.
Daniel Thirteen-Twelve

Good to see some one beats me to the point with the warning ;)

I have also seen several examples fail (spectacularly)
All from people thinking "that is now sorted for life"
Some rubbed on something others had no aparant wear
They should be checked yearly at least (lets say each time you grease the kingpin)

and to add
A midget should be able to stop anny where you want!
The pedal will feel diffrently from a modern car.
And you will need to aply more force on the pedal.
But you should be able to lock up the wheels.

It is a sum of speed and mass that dictates stopping power.
Since the midget does not weigh a lot you only need small brakes

racers and modified fast midgets will deviate from this logicaly since they poses a far greater speed potential
Onno Könemann

Thanks for the warning Deborah.

Since my rubber flex lines are new (front & rear), I think I may leave them alone.

I'm still looking to find a little better pedal feel.

I did find some sloppiness in the master cylinder plunger rod & clevis pin last evening...installed new pin & it felt better, might order a new rod.

Bill, you're probably right...I need to learn the limitations of the system & try to stay in those limits!

Thanks all,
Dave
Dave Rhine ('78 1500)

Debs, remember I had a SS back line go whilst having my MoT (glad the car was stationary when happened.


So i agree with you 100%

(Split was caused by a prop strike)
K Harris

I've got Goodridge lines for my Mazdas and they are certified for US DOT and TUV. That's fairly recent; formerly no SS flex were approved. This is as stated a matter of some manufacturer paying to do the tests, but at least IF it passes then they can't be too bad.

Use of flex lines for long runs where pipe would do is not a good idea; the flex lines still swell much more than the corresponding pipe and are more subject to damage.

Dave -
If you replaced rear shoes they may not be bedded in yet - it takes a good while since the rears do so little work. Put the handbrake on hard to eliminate this contribution for checking. Also front pads need to bed in - either causes mushiness.
Also check that all bolts and especially flat washers are installed on anything related to the MC mountings, flex of the mounts/firewall is a serious contributor to mushy pedals. Common to find no washers and less than half the bolts on the mounts. If you set up a dial indicator on the MC and watch while somebody really stomps on the brake you can be impressed and frightened sometimes! There's a lot of force on the tin that it's bolted to, especially rusty tin. People who want really solid brakes brace cylinders and mounts a lot.

FRM
FR Millmore

Thanks FRM...hadn't thought about the mounting bolts requiring flat washers.

Just a new clevis pin got rid of a little slop...I'll install new bolts, washers, etc. on the M/C & pedal box mounts this weekend.

I have noticed some flex in that area...

Dave
Dave Rhine ('78 1500)

Dave -
Study it a bit to see if adding some flat bar or angle would help. My only available carcass is outside and buried in snow, so I can't do it.
Very exciting when the whole MC/pedal assembly comes off the bulkhead! I had an XK120 that somebody had put a whole pedal/MC from some American car in - hung with two cheap ass 1/4" stove bolts and perforated plumber's strap.

FRM
FR Millmore

FR

Just got back in from the garage...replaced all the bolts & installed new flat & lock washers on the pedal pedal box mounts.

It firmed that area up quite a bit! Not as much flex/movement...thanks for the tip. No rust in the bulk head, that's one of the reasons I bought this car...NO RUST!

I was amazed when I first looked at the car...this thing should have been rusted out, but it wasn't. I'm still finding VERY little rust anywhere! It apparently lived a sheltered life.

The only problems I'm finding is with amature/shade tree repairs & maintenance, but soon should have all that sorted out!

I'll drive the little beast around for awhile to seat in the pads & shoes, re-bleed the system & adjust the shoes & go from there.

Thanks again,
Dave
Dave Rhine ('78 1500)

Even then I would be doing regular dye penetrant tests on a yearly basis (when the car is serviced) to check for possible failures.Deborah what good is dye penetrant on the woven cover of an aeroquip?
d brenchley

This thread was discussed between 03/02/2010 and 08/02/2010

MG Midget and Sprite Technical index

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