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MG MG Y Type - DOT 5 or not DOT 5 / part #1

Gentlemen

On March 24 of this year, I started a thread about changing from Silicon DOT 5 brake fluid to DOT 5.1 glycol brake fluid. All the replies, I received and for wich I am very thankful, had recommended to stick with the DOT 5 fluid.

After reading M.Long's comparison of different types of brake fluids, I am again two minds about what to do. If you care, please read the two attachments and the other two attachments that come with my follow-up post.

Why is it, that the US Army does not use DSOT 5 anymore?

Kind regards
Anton





Anton Piller

Anton,
I am confused why you started two threads instead of two posts on the same thread to get four images posted, unless it was just a simple mistake.

As you will hopefully get plenty of replies covering both ways I will put mine early and here.

Short answer stick with the silicone fluid you have already installed (longer answer below).

Longer answer to your second question. - What you have posted seems to be from an American perspective, they are a very big and populace nation, well states, with a huge amount of resources going to their military which means huge commercial interests.

As far as I remember it they wanted something like silicone because they had lots of vehicles stored unused but ready for, well, er, attack from everyone including themselves. They wanted to avoid having to changing the glycol fluids. Then, sorry but I do not recall the details, but IIRC, because (some of?) the vehicles never moved they still had problems and for probably many reasons the silicon was the "fall guy". Plus I would (only) guess they started to also store other vehicles less suited to long term storage with silicone.

Now, why I think you should stick with the silicone. I would expect that you was thorough in its change and application on your brake system. Many classic owners use it and recommend its use - but more importantly to me a mate of mine has used the same initial fill it in his summer use MGB since he fully restored the car over 20 years ago. His B is uprated and he does not drive slowly. He also put silicone into his daily drive Spridget which he uses over winter too, fully maintains himself and does not drive that slowly either. he has had no issues with using silicone, and apparently no maintenance with it.

The next bit I would have to confirm with him as I don't trust my memory but I think he said he just drained the glycol out and refilled with silicone.

This is contra to what another mate told me many years ago and he worked for Padgid brakes in the UK and had been in the motor trade all his working life up to that point.

If when changing to silicone you also changed items like modern made rubber flexi hoses those would concern me more.

I wished I had changed to silicone with my Midget but the thought of changing all the seals put me off and with my luck I could not risk not doing so. Although you will not be able to see it because of the small image size on the profile photo of my Midget there is a paint run where glycol brake fluid was split on the front of the front wing, but that is another story. Glycol is ancient technology and still used because it is so cheap and car manufactures can production cost to fractions of a penny/cent/yen.

HTH, I wonder what others will put. :)

Nigel Atkins

Sorry another typo, should have been -

. . . The next bit I would have to confirm with him as I don't trust my memory but I think he said he just drained the glycol out and refilled with silicone. This is contra to what another mate told me many years ago and he worked for Padgid brakes in the UK and had been in the motor trade all his working life up to that point, he said you needed to drain, flush and replace seals. This would have been good practice anyway as even my 1973 Driver's Handbook has to replace the fluid seals every 3 years or 36,00 miles (60,000km) whichever is the sooner.

Unless things have improved lately, I would not replace my seals already fitted that are functioning with modern made new rubber classic parts we get in the UK as many have proved to be of such poor quality with many only lasting weeks and months.


Nigel Atkins


Nigel

You were right in assuming that by mistake, I started a new thread to add pages 3 & 4 - instead of adding another post.

Thus, I add pages 3 &4 to this thread to make up for the plunder :o)

cheers, Anton




Anton Piller

Anton,
until you get further replies you might find it very reassuring to read threads in the Archives that basically show those that have actually used silicone brake fluid, some keeping it in the system for 20+ years, recommend it, in many different classics and modern vehicles, Tony Slattery in a 1936 SA.

Glenn Mallory just changed from glycol to silicone by draining and refill and no clean out and had no problems.

If you look in the Midget and Sprite Technical Archive you will find a thread from earlier this year called 'The brake fluid debate' with actual users.

There are other threads but as far as I can see and remember other than warnings from the likes of Lockheed(?) those that actually used silicone were for it, and those against hadn't used it (same as when I recommend modern oils).
Nigel Atkins

Before I dip a toe into this emotive subject let me make something clear. I believe it is your car and I have no wish to tell you what to do with it. I do feel, however, that most people make decisions on little knowledge (me included a lot of the time) or using so called facts from places, often manufacturers, who have a clear agenda in skewing what they tell you to their advantage and ensuring no criticism accrues to them in the case of an accident. Also people who have changed fluid types will stick by their decision simply because they made it, and those who haven't will take comfort in the truism that "if it ain't broke don't fix it". I don't claim to know where the truth lies but in order for us each to make up our own minds the attachments Anton offers are of some help. How far they get us however is thrown into some doubt by the inconsistencies they contain.

To start with attachment 1. This states that DOT3's ability to absorb water readily is a disadvantage whereas this becomes an advantage later on when considering DOT5, silicon fluid. The advantage comes from it keeping the water in suspension and thus not creating internal rusting in a silicon system. This assumes of course that you still have steel pipes. DOT3, or DOT4 replaced regularly, wins on this one for me. I also ignore the warnings about not storing opened DOT3, or for that matter DOT4, cans as personal experience proves that it is nothing more than the writer covering their back. Like so many things it may be theoretically true but in practice can be ignored. The warning at the bottom of the page about mixing fluids comes, in my opinion, into the same category. I will return to this later.

Attachment 2, on DOT4, suggests that it is like DOT3 but better, only more expensive. I would discount the cost as the piece is written for the US market, here in the UK I have not noticed any significant difference and anyway what's a bit of extra cost for our beloved cars. Once again we have the apocolyptic warning about not mixing fluids, along with the oft heard statement that all rubbers must be changed. It also contains an instruction to change it every two years. More later.

Attachment3, on DOT5, silicon fluid, is where it all gets really controversial and creates all the entrenched arguments I mentioned earlier. Leaving aside the oft heard, though rarely justified, references to the US military, a claim is made about it's boiling point, echoing earlier claims, suggesting higher is better. I'm sure it is, all other things being equal, but do we really need a high boiling point fluid. I'm sure those of you who regularly drive down steep alpine hills (you Anton?) or use their Y Type for racing as some have, will consider this an important consideration but for me it is neither here nor there and is of less importance than other considerations. It's compatability with all rubber formulations also remains to be seen especially, as Nigel rightly points, out modern rubber is of variable quality anyway and I would consider (a personal opinion to protect my back again) sticking with the original if not changing rather venturing into the unknown. I would disagree with Nigel, however, on the suggestion that new technology is necessarily better than old. To my mind tried and tested trumps shiny and new anyday. After all even the aforementioned US military have apparently changed their mind - or so people say! When we get to the disadvantages of DOT5 things get particularly murky for me. The claim that most problems are probably down to mixing with other fluids is less than categorical and stands in stark contrast to the concrete statement that a slight residue is sufficient to cause serious issues. This is a big scary statement but where is the evidence for this oft stated claim? Have you ever heard of any problems proved to have been caused by fluid mixing? It gets it's knickers totally in a twist when, in the fourth paragraph, it claims that silicon fluid is less compressible that Glycol and thus gives a slightly softer pedal! In all fairness it gets this correct later. I would discount reference to Harley Davidson and the suggestion that aeration is an ongoing problem other than the difficulties it may cause when bleeding and suspect any colour change is due to an additive to prompt repeat sales. I for one have never seen this so why mention it? There may be something in the difference in the lubricity as I have heard some anecdotal claims which ring true to me. This may be becoming mixed up with the oft heard claim that DOT5 causes swelling of the rubbers. Some TA/B/C owners have reported swelling of the m/cylinder rubbers such that the small return hole is obstructed causing the brakes to bind on and some recommend shortening the piston to avoid this. This is on a different m/cylinder from ours though.

Having said all that, and taking up a lot of your time, I will ignore the final page as little more than a summing up of what has gone before. I really must come clean though and tell you my experience which I believe is as valid as that of others, and more so than some (imho). When I got my YB it had silicon fluid in the system. I was unaware of this and in my ignorance I simply topped it up with DOT3 and 4 and can honestly say that I had absolutely no problems with the brakes in spite of it being my daily use car for some years. I only noticed it when bleeding the brakes one day and noticed the two types of fluid separating in the jar! As I said I won't tell anyone what to do and will agree with a lot of what is said as best practice but this has made it impossible for me to take much of what is said as gospel. So what do I do? I run DOT3 or 4, mixed is fine as it works well with no problems in our cars and is easy to bleed though I have to keep it off the paintwork. It makes good rubber lubricant as well. Thanks for listening.
regards
Ian
ian thomson

Well I for one enjoyed reading Ian's post, I'm very much for independent reports from real life and actual use (many classic vehicles are nearer to statues).

Good to get this conformation that having to have the system thoroughly cleaned and drained at change over isn't necessarily so as I've yet to ask my mate if I'd got his change without doing so was correct.

I don't think all modern technology is better than old or worth the effort to change to, but some are, yet are totally rejected just because they're not old. Many new technologies are basically very old anyway.

Ian's post offers the opportunity for Anton to easily change to DoT 3 or 4 at least, personally I wouldn't bother as 20 years use will be more more than I need. Water is the system was a worry to me but as users say they've been (real road use) using silicone and the brakes without problems for very many years had me dismissing this.

To me brake pedal feel is a personal preference the important thing is that the brakes fully work and work well. On many who about braking with silicone I feel often have tyres with lots of tread but hard through age and/or lack of use so as the tyres are so important to the braking their vehicles braking is below what it could be and they're worrying about the wrong item.
Nigel Atkins

I often find myself getting unreasonably irritated when I find the same old chestnuts being discussed on bulletin boards. I say unreasonably because having been at it since having bought a TC in 1966 when I was nineteen I arrogantly feel I have heard it all. After all there is a limit to how much you can say about a finite subject. I say unreasonably because the older I get the more I find to learn. One thing I have noticed is that along with the same questions being asked yet again is the friction which is created between old and new technology. As Nigel says a lot of technology is not really new having been around since the beginning of motoring, or for that matter, engineering. My feeling is if modern materials can breath new life into old design then use them if you can do so without spoiling a design which has been perfected over many years. Along with this I feel that they should be used within their limits, which means things such as leaving the braking distance the old system needs. Of course this creates problems with modern traffic but that is something we have to put up with as old car drivers and should not be used as an excuse for changing the car so that it becomes something it was never intended to be. I feel many people now coming into the old car movement (I don't like the word classic) want to change the cars because it is the fashion to do do, driven by commerce. In doing so they risk changing the very thing which attracted them to it in the first place. Five speed gearboxes is a case in point. If it keeps a car on the road then fair enough but if it replaces a perfectly good gearbox then it should not be done even if in pursuit of some notional idea of "reliability" of "driveability" and certainly not "comfort". "Safety is a grey area but, for me, seat belts are out. As I said "drive them within their limits". You will become a better driver for it. If you want those things you have bought the wrong car and probably for the wrong reasons.

regards
Ian
Notts UK.
ian thomson

Ian,
Nice article. I concur keep cars original, and use old brake fluid DOT3/4 not 5 which is more expensive and is not needed provided fluid is changed regularly.
You make an excellent point, drive the car to the way it was designed, the brakes on YA / YT/ YB if you allow for braking distance and follow principles of road craft manual, are absolutely fit for purpose and fine.
Finally use the car, car's develop their own niggles sat idle in a garage over winter months.
Richard
Richard Knight

A couple of things have confused me (altho' that's easily done), what makes anyone think that in average real life use there's any difference in braking between the types of fluid, subject to regular timely changes where required. And how is DoT 5 more expensive in the long run considering the cost of DoT 3 and 4 from many suppliers.

My point about brakes is that to maintain what braking is available as standard then the braking system as a whole needs to be maintained which includes the often forgotten tyres. Though I also think that brakes, same as tyres, get 'hard' from age and/or lack of use regardless of 'tread' left on them but those brakes could improve to some extent with use, a lot less so with tyres.

Certainly one of the very best improvement that can be made to a vehicle is driver training and the most dangerous part on the vehicle is the nut behind the wheel.

100% with using the car all year round when and where ever possibly and for at least 15-20 miles without stopping.

But you wealthy T-type owners rub it in a bit with boasting about garage ownership. :)
Nigel Atkins

Friends of the Y-Type

Wow, what a wealth of valuable information you cared to let me have! After reading it and considering all of your posts, I came to the conclusion to remain/stick with the DOT 5 Silicon brake fluid. Thank you all :o)

Why, I started this thread in the first place is the fact that the Y/T unfortunately use the 80 year old, pre-war brake system of just "one leading shoe". Remember what the claim of the early MG Car club used to be: SAFETY FAST - they even named their bulletin after it. This is just what I strive to achieve.

Because of this and because the car was in a sorrow state when I found it, fell in love with it and saved it from being scrapped, I renewed the complete brake system, including new copper/nickel/ferrum (CuNiFer) brake lines, bronze wheel cylinders, new brake hoses, soft brake linings, a re-sleeved master cylinder and new tyres of the correct type and size.

Actually, the restoration of the once sad wreck took me 35 years, with much of the hard labour done by myself. This included all the mechanical work, lots of welding and panel beating and some of the trim.

It's a pity, that at the time MG never used the twin leading shoe brake system of the YB with the YA & Y/T.

Your proud YT-Owner & Midnight Oiler
Anton

P.S.: one day, hopefully in the distant future, I will pass the car on to my grandchild (my son and my daughter each already "inherited" a TD each) and I want him to feel safe in it, despite being used to disc brakes, ABS, safety belts and so on......





Anton Piller

Anton,
you can be proud of yourself that looks lovely, well done.

I would want a good few lessons before driving a YT as I'm only used to driving 1960s cars (even though some were made in the 70s).

I would not want to be going too fast in it in case anyone missed seeing it was me in it, at the wheel or rear seat.
Nigel Atkins

great car
wonderful
i hope i will do it a little bit faster

would be great if i can contact you per mail
always difficult to get information for restoration
FT Franz

Anton,

I've said it before on the BBS but your car looks superb YT well done, must be up there with one of the best examples, there are a few now good condition YT's always really nice to see.

Some point need Y gathering in northern France, if only some UK Y owners would cross channel and few european based Y's travelled across from Germany / Holland and France etc.

Richard
Richard Knight

Nigel

Glad you like the YT. I do not think people would mix up the driver with the back seat driver - see attachment.
Before you can enjoy a ride in your Y-Type, there might be quite some work waiting for you - see the collapsable woodwork that fits into the door panels (made by myself).

Anton




Anton Piller


Franz

If you let me have your e-mail address, we can get in touch on special topics. Even though, I rather prefer to use this website, in order for other Y-Typers to take part. I gladly share with everybody.

Anton




Anton Piller


Richard

Thank you for the compliments. I'm glad you like what you see - the car even got a nice behind, don't you think :o)

Well let's see if Corona permits a meeting in France next year...

Anton




Anton Piller

Anton,
looks even better with your work.

We could be a trio as although I've not worn them in a long time I still have Halcyon Mk9 Super Jet Google.

I think we could easily upset some by using modern improved fluids in your YT and put all to good use in the coldest of winter and the hottest northern France could offer.

The people of France really enjoy seeing such cars and it makes you think of the better times to come.
Nigel Atkins

This thread was discussed between 29/11/2020 and 08/12/2020

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