Goodbye Aisin/Asco. Hello B.G.F./BIGGS

[lostmarbles]

After going to a lot of trouble to retain my original Toyota brake mastercylinder, I'm now dumping my Aisin clutch master and slave in favour of "B.G.F." and "BIGGS" models. (Both made in Taiwan.)

Why? Well because, unlike the brake mastercylinder, I can't find kits available to recondition them and there is no decent supplier of genuine Toyota parts near here (that I have found).

Anyway, I thought I'd share the experience because I started off quite worried about the quality of the non-Toyota stuff and whether I'd be harming my vehicle's all-important "reliability". Now - those worries have pretty well completely disappeared.

Here's some photos of the original gear:

[lostmarbles]

That Toyota stuff still looks OK until you take a closer look:



Here is a photo of all the clutch gear used on my BJ40 since it was new, including the new gear I'm about to fit:



I've painted this new slave cylinder, but since I'm inquisitive about the quality, I took it apart:

[lostmarbles]

I wasn't disappointed with the quality of manufacture:



Points against the BIGGS slave were that there was no "cap" supplied for the bleed nipple and no pushrod supplied. (I had to re-use the rod off one of the earlier slaves.)

You can see from this photo the differences in the rubber boots too. The BIGGS version seals on the threaded part of the pushrod so the adjustment locknuts become hidden within the boot. (Unlike the Toyota Aisin/Asco where they are exposed.) But that is not a problem really. Perhaps it is even nicer to have your nuts concealed .


Here's a photo of the slave under "maximum extension":

[lostmarbles]

And here it is in "minimum" position:



Looks nice eh?

Here's a photo of the BGF master with the pushrod removed:



I was going to blow that piston out with compressed air (because it didn't want to come out any further) but I could already see that the bore was perfectly machined and everything was nicely lubed so I didn't bother looking further to try and find faults.

Here's a picture of the BGF on the firewall: (PM me if you see a speck of dirt!)

[lostmarbles]

And here's the new braided stainless line installed. (I had to cut a slot in a stainless washer to act as a clip. I was going to use loctite beneath it but it's all so tight I didn't bother.)



And here's a photo of the BIGGS slave installed:



And here's another view of it looking directly up from underneath:

[map101]

Thanks for the information. As our fj40's get older we will all have to search for alternative options. You did good and have helped us all.
Thanks again and great show and tell. mark at map101

[lostmarbles]

Well I'm now very relaxed about my decision to use this gear. I can't see any of it failing in a hurry. (But time will tell.) It all looks smart too. (Don't know why I said in another thread that the BGF master looked "nasty".)

Hey. ----Maybe someone can give me advice on what they think caused the premature failure of the Aisin gear I've just removed? It lasted only 7 years/35,000kms!

There are a couple of things that I think could be related:

1. The top radiator hose recently burst off the t/stat housing as I bounced over a rough railway level crossing at speed. That covered my lovely clean engine bay in hot ethylene glycol mix . Perhaps some got in the clutch reservoir?
2. Then there was the time I was rather sloppy with the Marine Clean (powerful degreaser) just above the clutch reservoir. Perhaps some of that got inside?

Anyway, next time I poke the hose into the engine bay I'm sure as hell going to have the brake and clutch reservoirs covered in "clingwrap" or similar.

This photo shows some of the black crud on the Aisin slave piston:



And here's a photo of the fluid I drained. You can see the amount of black crud that has settled to the bottom. At first I thought that black stuff was "disintegrated rubber" from the seals but they look too good for that.

Whatever it is was sure seizing things up though. The last time I put my foot on the clutch (before removing the Aisin gear) it felt like the pistons were stuck fast - then they suddenly broke free. Not a nice feeling!!!!!!!!!

I'm using Castrol DOT4 brake fluid - But I doubt that is the cause. (Castrol doesn't have a bad reputation here.)

PS. Forgot - Some will no doubt suggest "lack of maintenance" for the premature failure. However I religeously change all the fluid once every two years (and I'm not prepared to do it more frequently than that. - Hell. Most people don't change theirs at all!!)

[inkpot]

Howdy! I have heard arguements that DOT 4 brake fluid is NOT compatible with the rubber parts in older rigs. That MAY be why the fluid turns black. Seems like there was a thread on this a LONG time ago. As for contamination, I doubt that you got cleaner or coolant into the reseviors unless you knocked the caps off. John

[FJFOOL]

Excellent post with great documentation !! I run an auto, but good info to have just in case. Thanks

[bsevans]

Originally Posted by inkpot

Howdy! I have heard arguements that DOT 4 brake fluid is NOT compatible with the rubber parts in older rigs. That MAY be why the fluid turns black. Seems like there was a thread on this a LONG time ago. As for contamination, I doubt that you got cleaner or coolant into the reseviors unless you knocked the caps off. John

I believe you meant DOT 5 brake fluid which is silicone based and not compatible with the seals in older systems. DOT 3 and 4 brake fluids are compatible with each other and the seals in older systems.

[lostmarbles]

Originally Posted by bsevans

I believe you meant DOT 5 brake fluid which is silicone based and not compatible with the seals in older systems. DOT 3 and 4 brake fluids are compatible with each other and the seals in older systems.

Yes. This agrees with what I thought too. I don't think my fluid type or brand is the problem here.

Dot 5 silicone definitely swells/damages old rubber seals. I converted my Triumph Bonneville motorbike to silicone and now it is lethal to ride (until I get around to fixing it). When you hit the brakes approaching a bend, the front disc calliper pistons won't release, so you end up taking the corner with the front brake still jammed on. (Needless to say, I'm not riding it till I replace the seals with silicone-capatible ones or do some other kind of fix.) The brake releases only when I stop moving!

My guess is that a drip or two of "Marine Clean" is capable of doing this damage and that it got in through that little vent cap on the top of the reservoir cap.

[corbinwelter]

looks good, also man clean your fj40 for once... that thing is dirty

[lostmarbles]

Thanks for the positive comments.

Couple of things I forgot to mention though:------------------------

The new B.G.F. master came without anything attached to the pushrod threads so I used the old Aisin stuff to connect it to the clevis pin on the clutch pedal. Also the rod was longer than the others so I cut about 5 mm off the end of the thread to match the length of the longer of the other two masters.

It is very helpful not throwing away old gear. Perhaps one day I may even get one of these cylinders bored and sleeved in stainless?

The only difference between the 1979 ex-factory 31410-60023 Asco and the Aisin 31410--60041 (that I fitted in 2000) seems to be a few millimetres in pushrod length!

The other thing I forgot to mention that may be of interest to other fussy people out there (like me) is that the new Taiwanese gear was able to be adjusted "exactly to spec". That is:

• Bare floor to top of pedal rubber = 215mm (I didn't need to readjust this because it was already set correctly via the "pedal back-stop" which I hadn't altered)
• Master cylinder pushrod play = 1.0 to 5.0mm (I set this at 3mm via the "master-pushrod-length" adjustment)
• Play at clutch release fork = 3-4mm (Hard to measure exactly but - I did that via the "slave-pushrod-length" adjustment)
• Pedal freeplay (movement till release bearing hits clutch fingers) = 30-50mm (I got 30mm and this measurement is actually just the effect "at-the-pedal" from your adjustment of the slave-cylinder-pushrod-length of course.

[FineWynsFJ40]

I see a speck of dirt

[Henry James the 47th]

Jeez Tom, I don't know, you must be slipping - that slave spring looks a little rusty, not to mention the end of the clutch fork. Rusty filth! And, and...the wiring loom - there's dirt on it!! How can you live with that?

[lostmarbles]

Originally Posted by FineWynsFJ40

I see a speck of dirt

Originally Posted by Henry James the 47th

Jeez Tom, I don't know, you must be slipping - that slave spring looks a little rusty, not to mention the end of the clutch fork. Rusty filth! And, and...the wiring loom - there's dirt on it!! How can you live with that?

Awwww Heck. I won't be able to sleep tonight now