Front r/h brake grabbing

[JohnBM]

I’ve put this on before. & I thought I’d solved the problem the front driver side locks up badly when I first want to use the car & only in the morning , more so on these colder , damp days this time of the year . A mate of mine who has a FC & very mechanically minded has been working on the car for several years & I think he’s starting wonder what the problem is . Some days it can take several minutes up & down the drive to usually stop the locking up ..( I use the car very frequently) on a previous morning & today I jacked the car up & took off the brake drum.& wiped down the inner machined surface ,& that corrected the problem. But you can’t keep taking the wheel off every time you want to take the car out .  The L/H front & rear brakes are ok .   Now I’ve noticed that the brake drums are original ID ie 9” they have not been machined .I’ve had the car since 1978.(you would I would have it sorted by now ) so the thickness of the linings should be 3/16” . The linings that are on it now are more like 1/4” so there’s not much movement in the brake pedal when braking . The l/h front is the same thickness but no problems , I was thinking of replacing the shoes & linings to the correct thickness ,this problem was going on even at the Toowoomba nationals,the fact that once I wipe down the drum seems to help seems strange . Anyway if anyone has had a similar experience I’d love to hear if or how it was solved , cheers John .

[Pahs59]

Should you try the spring holding the shoes together

[JohnBM]

No doubt it , it seems oddly enough once I wipe it down , the drum , like this morning , it was ok

[ardiesse]

John,

What you are experiencing is a design feature of Holden brakes.  GM engineers even termed it "morning sickness", and as you have discovered, it occurs when the weather is cold and damp.

The cure as published in "Accelerator" magazine is to chamfer the leading edge of the primary shoe and the trailing edge of the secondary shoe: the ends of the linings closest to the wheel cylinder, for a length of about half an inch.  Chamfering the inside and outside edges of the brake linings, to a depth of about 1/16" - 1/8", is also recommended.

The article also said to check the tension of the brake shoe hold-down springs.  If the shoe is not in contact with all three rubbing points on the backing plate, you need to put a couple of washers under the hold-down springs until the spring holds the shoes down correctly.

Does the morning sun shine onto the passenger's side of the garage?  Try parking the car the other way around in the garage for a few weeks and see whether that makes a difference.  Another short-term fix is to get a cheapo fan heater, set it to fan only, and place it under the front suspension so it blows air onto the RHF brake and wheel.

A longer-term cure is to improve ventilation in your garage.  Even air-conditioning (and no, I am not joking here.)

I have learnt to live with grabby winter brakes.  A gentle dab with my left foot on the brake for a few seconds once I'm in second gear is enough to make them behave.

Rob

[my8thholden]

John ..Rob has about covered it , I don't have much to add , one thought I have , are all four front shoes the same material ? Rivited or bonded ? ..a few years ago there was some pretty awful material around used in re bonding shoes , especially if its mixed on one car ...cheers Vern ..

[JohnBM]

Well , thanks Rob & Vern , very informative, it seems strange it’s just the front r/h wheel , the linings are from a company called Brake Bonders . as I mentioned the linings are a little out of spec thickness wise but when it’s going ok I have no problem . The return springs were mentioned , but I doubt replacements can be found nowadays in the event they contribute to the problem. The car is under cover & yes it can get damp in there. Don’t laugh but I might try out of curiosity my heat gun (carefully) if the car hasn’t been used for a few days & I know it’s going to lock up .    You would have thought others would be having similar problems? anyway, I have a complete set of shoes with 3/16” linings if I go down that track ,& try what you suggested ROB .many thanks .cheers John .

[mcl1959]

I have had that problem John and I never found a solution for it. Only one car I owned did this repeatedly nearly every morning I got it out. Mine was the left front wheel. I was wrecking quite a few cars at the time and what I did was took the entire front brakes off another car and put them on the problem car. No new linings or machined drums, nothing, just swapped everything.
It actually worked, the car never had problems again.
It does seem to me that it does not happen on every car, and I don’t know what the mechanism is that causes it.

Just a reflection.    Ken

[Rod]

I support what Ken is saying. I have an FC ute that never had this "disease". So much so, a couple of lining changes in-between as still no grabbing. A number of years ago I had the front end and subframe off to do some rust repairs. Once I put everything back together without any changes to the front end / brakes, I had the grabbing issue, interestingly enough on both sides (not at the same time though) when there is moisture in the air. I tried the chamfer approach with some success but not totally. Replacing the return springs fixed the LHS but I still get it on the RHS.

I had the old girl out this morning and sure enough the grab was present but resolved quickly. I have found if I drive slowly and put very light and I mean very light pressure on the brake at the same time the linings heat up and the issue resolves quickly.

I have an FE Sedan and it has never grabbed at the front end. It did at one stage on the RHS Rear but this was due to oiled linings.

Interest topic.

Rob are you able to indicate what edition of Accelerator that this issue was noted?

Cheers

Rod

[ardiesse]

Rod,

Volume 12, No. 4, May 1955.  Find it at https://hrc.org.au/holden/accelerator.html , and click on 1955 (May).

The archive contains priceless information for the Holden nerd.

Rob

[Rod]

Thanks Rob.

Have a guess what - I have been downloading many of these late this afternoon. Looks like some interesting reading now regional vic has gone back into lockdown. I just read one V20 No:1, Jan/Feb 63, which discusses modifying the Rear Main Bearing Cap to address rear main oil leaks. Haven't heard of that one. Need to consider that one when putting my FE motor together.

Thanks again Rob. Cheers Rod

[JohnBM]

Thank you everyone, I was having a beer with my mate this Arfo & explained again the problem, he went over what he believed was the issue, but was at a loss when I said that I could try to stop the grabbing on the right front. Wheel up & down my drive for maybe 10 minutes , finally giving up & take the wheel off , brake drum off ,a quick wipe down of the inside face .drum & wheel on & Bobs your uncle & away I went no problems.  A contaminated lining ? .I have swapped brake drums to no avail .we are going to replace the shoes & linings ( with the correct 3/16” thickness ) check flexible hoses again & the steel main line for obstruction. It’s something staring us in the face . Probably find it , then they’ll take my license off me because I. Too old .    We will prevail . Cheers John .

[ardiesse]

John,

You wiped away condensation on the surface of the brake drum, and the brakes worked without grabbing.  That's all there is to it.

Try the hot air gun.

Rob

[JohnBM]

Hi Rob , I know what you mean , but why only on the r/h/s ? 0n the way to the Canberra nats we got caught up in some really horrible weather rain wise & sure enough when we took off that morning bang went the Rhs brake again . Doesn’t make sense . Cheers John .

[ardiesse]

John,

That's a question about the fundamental capriciousness of the universe, at the local level at least.  (English Translation: It Beats Me.)

Tell me about where you park the car.  Is it shady or sunny?  Is it well ventilated?  Does it get damp in the winter?  Which side (if any) of the car normally gets the morning sun?  Is the RHF corner the most sheltered?  Which direction does the car face when you park it?

Rob

[JohnBM]

Well ,today we put the car on the hoist ,wheels off .drums off & took off the shoes ,so with the new shoes & linings at 3/16” thick we had to take out the cir clip on the bottom pivot point spring & reinstate on the new shoes .it was noticed that everything needed a wire brushing & red grease to get things moving again , the main adjusting bolt at the bottom where the slotted arms join meet on the right hand in particular had to be readjusted or slackened off to get them on . Not the case on the left hand side that was ok .which rang bells . Everything may have been a bit tight on the right ( the problem brake ) so the chamfer on the lining ends are correct .  I told my mate that this is all ok but why after just wiping the inside of the drum it worked fine ?? Anyway wheels back on ,brakes adjusted , away we went down the road , got up to speed , knock it out gear ,hands off steering wheel & brake hard , it didn’t veer at all .beautiful . I’m still not convinced .so there’s some cool weather on the way & I’m not going to drive it for a week , so that will test it , &. Are me a happy man if it has sorted the problem. PLEASE ,,,, cheers  John

[my8thholden]

Hi John .That is encouraging , the new linings will need to bed in even if you took a skim out of the drums ,the stiff arms where you said you had to adjust ,are you refering to item 6 on page 113 of manual ,"bolt and spacer assy,- brake anchor ''..there is really no adjustment there ,I found on my car when I pulled the front brakes down ,just by chance ,lucky I did at that point in time ,the very bottom of backing plate at that point was slightly bent ,the car must have slipped at some time in its life off a jack or stand ,in any event enough impact to bend the plate ,which in turn had that bolt out of true ,I had another good plate I used ..Also on the advice of a very good knowing friend , I have 10-tenths brake fluid in the car , 10-tenths is Penrite speak for "full synthetic "..he stated standard Holden brakes are problematic enough ( I didn't argue that point ) with out the added problem of other fluids that absorb moisture from the atmosphere ,especially vehicles that spend time parked..He has it in his Leyland Force 7V and no brake problems ..I posted an item on that procedure in my rebuild ,now in finished projects ..keep well Vern ..

[DougT]

Just on the last point from Vern, I have had Dow Corning silicone brake fluid in my FE since 1988 and never had any issues, as it is not hydroscopic it has never been changed. I believe it is now marketed as Dot 5 for motorcycles. In order to use it you would have to replace all your rubber components and give your brake lines a good flush with metho as the silicone fluid reacts with any rubber that has been in contact with standard brake fluid and makes them swell. Worth considering.

Doug

[my8thholden]

HI Doug ..Yes thats right , I did flush the system with metho ,I did only wash the wheel cylinder pistons and rubbers ,but did not replace ,those were new for about a year before I decided to change fluid ,I must confess I was not aware of existing rubbers being in contact with DOT 3 or 4 fluid reacting that way ,thanks for the tip ..thinking about it ,its a bugger !!!!!keep well Vern ..

[DougT]

Hi Vern, should your brakes become less effective over time I would be looking at the brake hoses in the first instance as the inner lining swells and restricts flow. Just a thought on the grabbing brake issue, has the front end been removed and if so, could components i.e. spacers been put back together in different locations? The reason I ask is this effects the caster angle on either side of the vehicle resulting in different forces at play on each wheel.

Doug

[JohnBM]

Thanks Vern &  Doug, I’ll get back on here with the results , fingers crossed .