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MG MG Y Type - Oil/fluid/grease all over front wheels?

I wonder if someone can help me please. I have a 1953 YB with all original running gear.

Today four of us (family) drove 50 miles to Silverstone for the MG event. The weather was warm and sunny, and I pushed the car on a bit and was cruising at 60mph or thereabouts.
When I reached Northampton and started to hit a little traffic at the roundabouts, the car felt like it was lacking a little power, the temp gauge was rising to a level I'd never seen before (100), and at the same time I noticed the brake pedal was very hard. Brakes still worked ok.
When we stopped at one roundabout my wife thought she noticed smoke, but wasn't sure and by then we were on the move again so nothing was checked.
I then noticed that the brake pedal had lost its hardness, and the car also seemed to run easier - as if binding brakes had been released. The temp gauge also confirmed the coolant temp was dropping down to just above the normal level of 80.
When we arrived at Silverstone, I was alarmed to see that both front wheels had what looked like engine oil running all over them, emanating from behind the hub caps. I smelt the 'oil' and it didn't smell like brake fluid, but looking behind the wheels I couldn't see anything wet or suspicious. On removing the hub caps it was very wet, and seemed to be coming from the hubs themselves.

I was at a loss to explain it.

I then spoke with an extremely helpful chap at the Octagon stand (Dutch or Swedish by his accent?) who said it could have been incorrect adjustment at the brake master cylinder, causing hot fluid to be expelled under pressure. This definitely sounded plausible, but on returning to the car I still couldn't get the fluid to smell like brake fluid - it was effectively odourless, and I wondered if it could have been overheated grease.

It's now 11pm and I will check the brake fluid level in the morning (the car drove home fine!!??), but I wondered if any of you guys could add your thoughts please?
It it's brake fluid I should find out when I check the level. And if so then would it be sensible to have the brakes overhauled and synthetic fluid used? (I don't mind the cost if it's likely to stop the fluid overheating again.
If it's oil Lord where has it come from?
If it's overheated grease what can be done?

All offers of help are MUCH appreciated.

P.s. by the way, the Silverstone event was great - it was good to see nearly 10 YA/B's there.

Cheers,

Phil.
Phil Gilbert

On checking the inside of the wheel hub caps the morning after (in the shade and therefore reasonably cool), I am certain that it was grease which had become hot and subsequently expanded out of the hub.

However, two questions still remain which I would very much value your help:

1. Why would that cause the hardening and subsequent softening again of the brake pedal pressure?

2. Does this indicate that an incorrect grade of grease has been used, and if so what impact/damage could have been caused?

Many thanks,

Phil.
Phil Gilbert

Phil:

This is almost certainly overheated grease escaping from the felt seal on the hub. I had a similar episode recently after adjusting the brakes, and it appeared that the brake pedal "hardened". I suspect you may want to adjust the master cylinder pushrod to pedal linkage clearance, so as to allow the master cylinder piston to return further and fully uncover the drilling which allows fluid to return to the m/c reservoir. If this does not happen correctly the system will not depressurise as the pedal is released, and the brakes stay at least partly on.
Let me know what happens. Glad to know Silverstone was good.

Tim
Tim Griggs

Phil, At first reading I would suspect that you have more than one problem - all related, I expect, to temperature. I cannot see the water temperature rise - and fall, as being related to the brakes. Check your thermostat. XPAGs run fine without a 'stat if only used in the summer. You say the brakes went hard - and then soft, and were OK on the way home. The "fluid" which you found on the wheels must be implicated in this. BTW brake fluid has a distinctive taste - just a spot on the tongue, I find this the best identifier. Tim's point about the pedal clearance may well be a reason for the pedal to go hard - and perhaps suddenly release, but would not explain why brake fluid would be released from the slave cylinder(s). For this to happen a slave seal would have to have been dislodged, and I doubt that the brakes would have been OK subsequently. Heat could easily force molten grease from the bearings especially if you have the felt seals fitted, but the only effect this would have on the brakes is to make them ineffective on that side as it coated the drum (brake fluid would have done the same). The pulling to one side would have been obvious - unless both sides were affected - and then the brakes would have been even less effective than they normally are. The pedal would have been very hard though! and stayed that way! As for the "smoke" I have often thought that I saw smoke in the cabin of my YB but it has always cleared before I could be absolutely sure. It has always happened on stopping momentarily. I suspected the wiring but thorough checks found nothing. I now suspect now that it is caused oil dripping on to a hot exhaust and coming up though ill fitting floorboards (it is a Y type after all). As the fluid on the wheels is the most obvious sign I would have the drums off (have you got a suitable puller?) and find out what is going on in there. Good luck and let us know how you get on.

Ps. I probably have photo of your car as I took one of the Ys line up on Sunday as I was feeling guilty about having come in the B.
IAN THOMSON

Thanks for the replies. I strongly suspect Tim's idea is the correct one, as the gunge inside the hub caps is definitely not brake fluid but grease (when I first saw it it was still hot and 'runny', but the morning after it had cooled to, well, grease!)
Therefore I reckon it was likely that there is a problem with the adjustment of my brake master cylinder, causing brakes to semi-bind when the fluid heated up, causing the engine to overheat because it was like pulling a car and a family of 4 up a 1 in 5 hill, causing the grease to overheat and burst out, causing the smoke!

I will investigate further and report back......
Phil Gilbert

Further note to Ian.
As we only came over on Saturday afternoon, and was directed LEFT when we drove in, we ended up parked behind the main grandstand - a long way from being part of the Y-type line up! (even though I asked for directions to the rest of the classic cars......)
So my car will not be in the photo I'm afraid.

However it was very interesting to see the others (having only owned mine since March this was the first time I had seen other Y's in the metal), and what interested me was that mine must be one of the only ones still around with.....oh no this needs to be a different thread - I'll add one later.

Phil.
Phil Gilbert

Update.

At the weekend I removed all four wheels from my YB (using the Jackall system supplemented by stands of course) and renewed my brake fluid with modern higher-performance fluid.
The first wheel took a while as I not only flushed out the wheel cylinder and pipes, but the master cylinder as well. The other three were pretty quick.
The old fluid looked a little tired and slightly oxygenated (fyi a little less that 1 litre is needed to replace it all).

I also checked the source of all the grease from the hot run, and it had clearly come from the grease-packed front hubs. After removing the covers I replenished with fresh (high melting point) grease.

I also took the opportunity to adjust the rear brakes, although they only needed a couple of notches.

All seems well, and the brakes are definitely better (less spongy, bite better).

Phil.
phil gilbert

Phil:
Glad to hear the problem is fixed... are you now using silicone fluid? I adopted this for my car during the rebuild four years ago and it has worked well with a new set of cylinders and seals - it would be interesting to know how you find it over time in an existing system.

Tim
Tim Griggs

I had considered using silicone, but the price difference was steep. I used a good quality non-silicone fluid - costing about £10 a litre rather than the cheaper type at £5-6.
Probably nothing in it, and now that I've done the job and have ssen how easy it was, I'll be happy to make it a bi-annual job (it's always nice to get the wheels off to have a good look around as well).

Phil.
Phil Gilbert

This thread was discussed between 23/06/2001 and 10/07/2001

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