Handbrake failure... Help please

[lostmarbles]

Hi all.

Some may know already that I had trouble getting my BJ40 declared roadworthy by the authorities here, and that soon after passing, I developed handbrake problems.

I was suspicious that oil-seepage into the drum from my transfer case may have been the cause so I promptly ordered a couple of seals and a couple of stake nuts (the extras to be held as spares).

But then I took the cruiser for a drive yesterday and tried applying the handbrake on the move...

It resulted in a "grating noise" which got me to thinking that it must instead be some sort of mechanical failure...

So in I went this morning..

As you can see here, the drum is dry so oil certainly wasn't my problem:

Instead this was:

 

[lostmarbles]

I'm always very gentle with the handbrake because I see no need for brutality... (and let's face it, unlike most 40-series components, it's not really very sturdy).

Here's a close-up of the clip that let go:

You can see that the centre has been sheared right out of it!!!! <expletive>

Has anyone else experienced this? .... and if so do we know any ingenious solutions for idiot-proofing these pins and clips ?

And just to prove that I'm an idiot too....

I had made a mental note to turn the cruiser the other way around in my sloping driveway before tackling this job .... but somehow I just went straight into it this morning without doing so...

I didn't drain the transfer oil with the justification that "it was already quite fresh" and "I could save myself the hassle of draining and refilling".

Anyway... You guessed it ....... I had to keep jacking the rear higher and higher to stop oil from dribbling out the seal onto my pristine (OK ....just ordinary) driveway:

 

[snaggletto]

That pin should only ever see radial or shear load. I would inspect the linkage pivots etc. to make sure the lever arms are not twisting out of plane when you pull the parking brake. If all seems normal, just put in a new pin and I bet it lasts forever.

 

[sadam_husain]

doesn't really answer your question about idiot proofing the broken pin and probably not what you want to do with your immaculate condition stock cruiser but putting rear callipers with handbrake/parking brake/emergency brakes on the back of both of my cruisers was one of the best things I ever did when I put my fj40 on the trailer and hook it up to the back of my fj75 I can park on a slope and apply the handbrake and leave the truck and loaded trailer sitting there with the engine still idling and it doesn't creep or roll away

 

[antFJ]

i had one let go on the way back from heavy wheeling. I heard a metal to metal whirring sound and it was that arm dragging while the drum spinning. I just replaced the pin with one from my used parts stash and haven't had a problem since. I'm not sure what caused it in the first place.

 

[handcannon]

Just out of curiosity, what donor was used for the disc/hand brake parts? Since you are in NZ I'm guessing it is something not readily available here in the USA.

Don

 

[kiwidog]

Hi Tom,

Please don't crawl under your 40 with it sitting on the 4x4 blocks the way you have them stacked. They should be 90 degree double cross stacked, you will need more blocks but it will be safe.

Had a similar thing happen to my 1980 FJ40. The C type clip didn't shear off like yours but all I found was couple of small pieces of the clip. Think i just put another one on the same pin and put it back to work. It was still working OK until the 40 was taken out of service for a major rebuild /restoration. Don't over think the problem, run it with MrT's set-up and check it after a 1000k or so
Great looking 40 pity it's a diesel !!!!!!

Thanks jb

 

[sadam_husain]

Just out of curiosity, what donor was used for the disc/hand brake parts? Since you are in NZ I'm guessing it is something not readily available here in the USA.

Don

you guys probably had a few of them over there, 1985 Subaru leone front callipers (the handbrake mechanism is on the front callipers), they have always been a popular calliper for rear disc conversions over here but there isn't so many of them left these days

 

[Bambi Girl]

Hi Tom
Interesting problem.
From your photos these are my thoughts.
Am I right to say that the retaining clip has sheared at the same diameter as the parallel pin?
If so what tell tail signs are on the clip and the failed piece of clip that is still attached to pin.?
One would first think that a load has been applied to the parallel pin at the retaining clip end causing the clip to shear.
I can not see that being the case.
I'm more inclined to think the clip has been a loose fit on the pin and over the years it has been rotating away while a hair line crack has formed . This crack has spread the diameter of the pin.
It would nice to examine the parts more closely to see if this theory has Merits.

40 something years in engineering and I can not say I have seen a fail like this.
Good thing you were not in the middle of your trip.
A new pin and clip would be my solution
Or a parallel pin , washer and split pin is another solution.
Cheers Peter


...via IH8MUD app

 

[76technician]

I second a chronic and not an acute cause. When I replaced my brake pads this summer all I had were some second-rate aftermarket ones (from CCOT, never again). Currently, until they wear, they are either full on (can hear it when driving slowly) or at one notch out it takes two hands leaning back to get them to keep it parked. If a regular diet of me leaning back and "rowing" with the handle hasn't broken my pot metal components, I can't imagine a bureaucratic hand managing it!

 

[JohnnyC]

Tom I recall there being a thin washer under the horseshoe clip... Hadn't had mine apart for quite some time so I could be thinking of another vehicle

That would make a tighter and more exact fit as to not have any movement twisting the pin IMO

 

[snaggletto]

Tom I recall there being a thin washer under the horseshoe clip... Hadn't had mine apart for quite some time so I could be thinking of another vehicle

That would make a tighter and more exact fit as to not have any movement twisting the pin IMO

Excellent observation.

 

[shelfboy1]

if thats the original just replace it and be good for many more years ,i never had one fail in the 44 years i have driven 40 series vehicles

 

[lostmarbles]

That pin should only ever see radial or shear load. I would inspect the linkage pivots etc. to make sure the lever arms are not twisting out of plane when you pull the parking brake. If all seems normal, just put in a new pin and I bet it lasts forever.

Thanks Snag

doesn't really answer your question about idiot proofing the broken pin and probably not what you want to do with your immaculate condition stock cruiser but putting rear callipers with handbrake/parking brake/emergency brakes on the back of both of my cruisers was one of the best things I ever did when I put my fj40 on the trailer and hook it up to the back of my fj75 I can park on a slope and apply the handbrake and leave the truck and loaded trailer sitting there with the engine still idling and it doesn't creep or roll away

Looks good Marty. .. (But as you know, I like to keep mine basically stock so such a mod would be far too radical for me.)

i had one let go on the way back from heavy wheeling. I heard a metal to metal whirring sound and it was that arm dragging while the drum spinning. I just replaced the pin with one from my used parts stash and haven't had a problem since. I'm not sure what caused it in the first place.

Very good-to-know ... Thanks

Hi Tom,
Please don't crawl under your 40 with it sitting on the 4x4 blocks the way you have them stacked. They should be 90 degree double cross stacked, you will need more blocks but it will be safe.
Had a similar thing happen to my 1980 FJ40. The C type clip didn't shear off like yours but all I found was couple of small pieces of the clip. Think i just put another one on the same pin and put it back to work. It was still working OK until the 40 was taken out of service for a major rebuild /restoration. Don't over think the problem, run it with MrT's set-up and check it after a 1000k or so
Great looking 40 pity it's a diesel !!!!!!
Thanks jb

Thanks for the warning JB.. I am of course living in an area where earthquakes are prevalent too ...

I've decided to drain the transfer oil so once I've done that I can let her back down. Maybe today .. But I'm going to be waiting on parts and have other pressing things to do today.. (Yesterday it was blowing a gale so the dribbling oil was blowing all over the place and I was stinking of the EP-oil-additive all evening at work last night despite having a decent shower before going there. LOL)

Hopefully my mate Pete over in Oz will have the parts I need. (I asked him for the levers, pins and clips yesterday but haven't heard back yet.)

As for the diesel comment ... I think I'm best ignoring that .....

Hi Tom
Interesting problem.
From your photos these are my thoughts.
Am I right to say that the retaining clip has sheared at the same diameter as the parallel pin?

Yes. That's right Peter

..If so what tell tail signs are on the clip and the failed piece of clip that is still attached to pin.?
One would first think that a load has been applied to the parallel pin at the retaining clip end causing the clip to shear.
I can not see that being the case.
I'm more inclined to think the clip has been a loose fit on the pin and over the years it has been rotating away while a hair line crack has formed . This crack has spread the diameter of the pin.
It would nice to examine the parts more closely to see if this theory has Merits.
40 something years in engineering and I can not say I have seen a fail like this.
Good thing you were not in the middle of your trip.
A new pin and clip would be my solution
Or a parallel pin , washer and split pin is another solution.
Cheers Peter..

Rest assured that I'll have my forensic kit (and camera) out when I remove the shoes, levers, springs etc .... and I'll try and come to some conclusion then...

Your input here is valued...

I second a chronic and not an acute cause. When I replaced my brake pads this summer all I had were some second-rate aftermarket ones (from CCOT, never again). Currently, until they wear, they are either full on (can hear it when driving slowly) or at one notch out it takes two hands leaning back to get them to keep it parked. If a regular diet of me leaning back and "rowing" with the handle hasn't broken my pot metal components, I can't imagine a bureaucratic hand managing it!

I've gone back and removed what I said about the damage possibly because caused during my recent vehicle inspection. That was unfair (and I was thinking about it yesterday while I was working). The cause could just as well be an assembly problem (caused by me) in previous years because I have most definitely been in there before.

Tom I recall there being a thin washer under the horseshoe clip... Hadn't had mine apart for quite some time so I could be thinking of another vehicle
That would make a tighter and more exact fit as to not have any movement twisting the pin IMO

You are indeed correct Johnny. There should be a washer there. At the moment I'm not sure if should sit directly under the C-clip or between the two levers. But anyway, I saw no sign of one when the pin and clip fell out.

So I think you're onto something important here.

if thats the original just replace it and be good for many more years ,i never had one fail in the 44 years i have driven 40 series vehicles

Great to know... I am trying to get new parts coming in.

That pin (that fell out) shows tapering-wear to me ....which is likely to impose a shearing-load on the C-clip (aka horse-shoe clip) IMO. The holes the pins sit inside will no doubt have similar wear. Hence my desire at this stage to fit quite a few new parts.

Thanks again to all contributors!!!!!

 

[JohnnyC]

I did a quick look at parts diagrams myself and it does seem like it should be just under the horseshoe clip

 

[lostmarbles]

I did a quick look at parts diagrams myself and it does seem like it should be just under the horseshoe clip

Thanks Johnny. No doubt you are correct. (I haven't had the time to look myself yet.)

 

[handcannon]

Thanks for the reply sadam! We don't have that particular model over here, but others similar, or maybe the same just with a different name. I do have a pair of those calipers buried somewhere out in the shop. I picked them up several years ago when I was junk yard hopping, thinking they might be useful for having the handbrake included. I'll have to dig them out and refresh my mind on just how they are configured. I may not come up with anything right away, but I may wake up in the middle of the night with one of those AHA! moments after dreaming of my 40. Any pics or info on how you adapted them to your rear axle would be appreciated, maybe in a different thread so as not to hijack Tom's thread.

Tom, sorry for the hijack, but after that pic I just had to find out what they were. In the back of my mind I've been puzzling over problems I'm having with my handbrake.

Hope you come up with a definitive answer for what caused your problem.

Don

 

[lostmarbles]

....Tom, sorry for the hijack, but after that pic I just had to find out what they were. In the back of my mind I've been puzzling over problems I'm having with my handbrake....Don

No problem Don/Marty..

In my view, ih8mud is all about helping each other with our cruisers ....in a relaxed atmosphere too..... and that's exactly what we're all doing here..

(I'm hardly one for steadfastly remaining on topic and I even revert to a bit of chat in some tech threads as you probably know .... so I'm entirely at ease.)



PS. I'm having trouble contacting my preferred vendor in Oz at the moment ... so fixing the handbrake is delayed...

 

[handcannon]

No problem Don/Marty..

In my view, ih8mud is all about helping each other with our cruisers ....in a relaxed atmosphere too..... and that's exactly what we're all doing here..

(I'm hardly one for steadfastly remaining on topic and I even revert to a bit of chat in some tech threads as you probably know .... so I'm entirely at ease.)



PS. I'm having trouble contacting my preferred vendor in Oz at the moment ... so fixing the handbrake is delayed...

Thank you! That is what I appreciate so much about Mud. There are some other forums that I frequent occasionally that are not so forgiving.

Don

 

[lostmarbles]

I've got parts on the way so I'm already thinking about reassembly (even though I haven't got to the bottom of the failure yet)...

Question 1: Has anybody got any idea why Toyota has this thin shim here under the thick washer?

I can't see what purpose it serves and I'm thinking of leaving it out (because it is paper-thin and on the verge of disintegrating anyway)


And while I'm thinking of this area, I've usually used silicon sealant on the splines to try and stop oil from flowing between the male and female splines (and I believe this is common practice for others here to do this too)...

But this time around.... I'm having second thoughts about the logic of doing it..

Every time I have ever separated the driveshaft yoke-flange from the park-brake-drum enough oil has poured out to convince me that the gap between the two has been completely filled with oil... So the silicone sealant has ALWAYS failed yet that has never been a problem because when those four flange bolts are tight, that space is oil-tight.

Furthermore, there's always sufficient play between the male and female splines in the transfer-output and drum respectively ... to ensure the silicone sealant can NEVER hold the oil back.

And the only thing that stops oil getting inside your drum is your seal just behind your backing plate (which couldn't care less whether you apply silcone sealant to the spline area or not.

So the second question is ... Anybody see any problem with me omitting the silicone sealant this time?

By the way.... there's no mention of using silicone sealant on the splines in the FSM so perhaps that already gives me the answer I want to hear...