Need help with brake issue on R Type

hermansings · Joined: 15 Apr 2020 Posts: 3 Location: Kolsås, Norway

Hi! My name is Herman, and I'm a member from Norway who own a '53 R Type I'm very fond of. On my last trip with the car, the front brake on the right hand side overheated quite badly, with some white smoke emerging from the brake when I parked. There are no "bad" noises or squeaking from any of the brakes. I jacked up the car and spun both the front wheel on the right hand side, and the front wheel on the left hand side to compare them. The wheel on R.H. side spun easily with no friction stopping it, where as the wheel on L.H. side stopped almost immediately. I've also adjusted the front brake adjuster screw a bit in case the brake shoes were to close to the drum, but it didn't help. Does anyone know what might be causing this problem?

I have tried to remove the brake drum, but the three countersunk headed retaining screws are impossible to remove, so I fear I have to destroy them to get them out. If that is the case, does anyone know what type of screws I need to replace them with and/or where to order them?

All helpful answers will be highly appreciated.

Regards

Herman

Philip Edginton · Posted: Mon Jun 29, 2020 7:39 pm Post subject:

Look up, Flyingspares.com

they have them in stock, see below for part number.

Part Number RG4444P
Chassis Range Applicability 1946-1955 RR Silver Dawn & Silver Wraith, Bentley MkVI & R Type
Stock Availability Stock Item - usually available for immediate despatch

John Murch · Posted: Tue Jun 30, 2020 4:48 am Post subject:

Hello Herman,
Welcome to the forum, have you tried an impact screwdriver to remove the screws?
John

Christopher Carnley · Posted: Tue Jun 30, 2020 8:48 am Post subject:

The Rolls-Royce countersink angle is 60 degrees, not 90, so if you have to drill the screws, be careful.
You can usually start them by using a pointed punch at the edge of the slot and tap it anti clockwise.
The threads are 1/4" BSF.
There are two other threaded 1/4" BSF holes diametrically opposed and with 2 off 1/4" BSF set screws you can use them to jack off the drum.
Make sure that all the adjustment is taken off by turning the square adjuster at the rear of the drum.
Have you a copy of the Service Manual?
..

Martin Webster · Posted: Tue Jun 30, 2020 10:25 am Post subject:

Good morning Herman. Once you have removed the set screws, it is extremely important that you do not attempt to hammer the brake drums off from the back if they are reluctant to come off as the cooling fins on the drums are very brittle and crack very easily.
I would say that the overheating of the brakes could well be the result of old degraded brake hose. What happens, is that when you apply the brakes, a constriction occurs in the rubber hose and prevents the fluid from returning from the brake cylinder, which causes the shoes to remain in contact with the drums. As a precaution, I would certainly recommend that you change both front hoses and change the brake fluid before rebleeding.
I hope that you manage to solve your problem.
Kind regards
MARTIN
B88 HR

Martin Webster · Posted: Fri Jul 03, 2020 8:38 am Post subject:

Were any of the suggestions offered useful to you Herman?

Christopher Carnley · Posted: Fri Jul 03, 2020 4:32 pm Post subject:

No answer, came the stern reply.

Martin Webster · Posted: Sun Jul 05, 2020 12:08 am Post subject:

Still remarkably quiet isn’t it?

Christopher Carnley · Posted: Sun Jul 05, 2020 9:20 am Post subject:

We have gale force winds in Yorkshire, rattling the tiles.

Philip Edginton · Posted: Sun Jul 05, 2020 10:19 pm Post subject:

Down here on the south coast as well. still will keep all those idiots indoors rather than on those glorious hills and dales.
the beaches are clear. Did I hear it was also bad in Norway.

hermansings · Joined: 15 Apr 2020 Posts: 3 Location: Kolsås, Norway

Hi everyone!

My apologies for the far too late response! Philip is quite right, the weather up here is dreadful, and thus I escaped with my family up in to the Norwegian mountains. Far off the local Wi-Fi hotspots I'm afraid. I have since returned and thank you so much for all the suggestions! A pointed punch at the edge of the slot of the retainer screw worked wonders, and followed by some wriggling back and forth I got the drum off!

Thanks a lot also for the advice on new brake rubber hoses. I will certainly investigate further, but I have just a quick follow question. If the constriction causes the shoes to stay in contact with the drums when applying brake force, shouldn't there be a constant friction leading to scraping noises or similar? Before my vacation, I reluctantly had to move the car, as it was parked at a friend of mine's after I first discovered the overheating. It was a 30 minute drive, but I drove at night with few cars on the road, and managed to avoid any application of the brakes for the whole trip. When I arrived, there were no signs of overheating from the brakes. In fact, they were quite cool. Would this be possible if the brake hose is degraded?

Again, I really appreciate the replies and suggestions, and I promise that I won't take so long to respond again;)

Hope everyone are enjoying their vacation! Very Happy

Martin Webster · Posted: Tue Jul 07, 2020 10:21 pm Post subject:

So glad to hear from you again Herman and welcome back.This time last year we were in Norway visiting the Norwegian fjords and I envy you being able to visit the mountains.
Regarding the brake hoses, the constriction depending upon how old or degraded the hose is will eventually and slowly allow fluid to return from the slave cylinder to release the brakes but as you have already mentioned, the brake lining can get very hot whilst in contact with the drum in the meantime.If the hoses have not been changed recently, it would be a good starting point. It would be prudent to also check the linings at the same time and take the glaze from them with some brake cleaner and some emery cloth. Clean the drums with the same cleaner.The fact that you didn’t use your brakes during your recent 30 minute trip without any problems tends to indicate that it could indeed be the hoses that are at the root of the problem. Good luck and let us know how it goes.
Martin
B88HR

hermansings · Joined: 15 Apr 2020 Posts: 3 Location: Kolsås, Norway

It's great to hear you've visited the Norwegian fjords. Feel free to contact me if you ever should visit Norway again and want some traveling tips, or around the Oslo area and want to have a chat about cars!

Thank you for elaborating on the brake hoses. It does make a lot of sense that degraded old hoses explain the problem now. I will certainly check both of them in the front, and the brake shoe linings thoroughly, and get back to you with the results.

Christopher Carnley · Posted: Wed Jul 08, 2020 3:14 pm Post subject:

Since he got the drum off so "easily," I think that the brake may have been over tight.
The servo only action would possibly rule out the flexible pipe degeneration.

Martin Webster · Posted: Wed Jul 08, 2020 7:18 pm Post subject:

Yes Chris, that’s a distinct possibility isn’t it? Something to look forward to !
What interesting (or otherwise) projects in the pipeline?
ATB
Martin

Christopher Carnley · Posted: Thu Jul 09, 2020 8:49 am Post subject:

On second thoughts Martin,it could be a seized wheel cylinder, and a complete brake overhaul should be done.

It has been relatively quiet, with only a few damaged gearboxes from the Belgian side.
I got involved with a "Blue Train" project for Theodore Agnew MP etc, being carried out by a firm in Norfolk, based on the MK VI chassis and a load of "scrapings up". The gearbox salvage was scrapped, only the gear set and a few other parts from the axle were used.
Then I received an R Type engine B21U, from a US car,fired and left out for 50 years.Apart from front end rust it is in remarkably good condition and had been rebuilt by R-R, in the late 50,s I think. It had had a new camshaft and tappets.
The problem now is that boring out for the desired 3 3/4" pistons has revealed sand core slip problem-holes. Nos 1 and 4 had been fitted with bottom liners when it was made to seal the bores.
It was quite a problem at the time.
He wants an S1 H.C cylinder head fitted which is taking a groaning age to fit up from a totally robbed out one.
I had swapped a pair of HD8,s for a selector mechanism for the gearbox with Jeremy Padgett, so I have gone for simplicity with a pair of Jaguar type HD,s.
Now it is the cold monsoon season.
I got 9 off new first gears for the gearbox jobs delivered on Tuesday.

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

Perhaps of interest to folks re-doing brakes.

For several years now, we have been using a softer brake lining material on our prewar Silver Ghosts, Phantoms etc, and on my veteran cars. The increased stopping performance is quite remarkable - but it's a bit of a trade off in terms of longevity. They will not last as long, but probably still long enough for most owners unless they are putting lots and lots of miles on the car.

We've been using what is commonly called "elevator brake" material, or "punch brake" - it has a coefficient of friction of 0.4-0.45. Bonded, not riveted.

The improvement in braking is so remarkable the trade off is well worth it.

Martin Webster · Posted: Thu Jul 09, 2020 1:53 pm Post subject:

That seems a very high mu value Dan, what is the value for conventional modern brake linings I wonder and are they significantly higher than the old unmentionables.