Slight oil leak around clutch master cylinder boot

[Touz]

Hi all, I notice this odd noise in my HJ75. When in gear and slightly depress the clutch pedal (not engage, just in that free play zone), there is this odd noise kind of like a bubbling!? I can't find the right word for it. But anyway, I inspected the pedal and where the pushrod enters the master cylinder and there is a bit of oil coming out around the rubber boot. Recently I fiddled around down adjusting the pedal height and freeplay - is it possible I damaged or displaced a seal? I wasn't that careful when doing it.

My question is: is a bit of oil around the boot to be expected or is that the sign of a broken seal? I've had to replace a master cylinder in a previous car (Hiace) and in that situation there was oil all around the pedals, that was a serious leak. In this situation it's just a bit oil around the boot, so maybe nothing to worry about.....

 

[Felde]

Hi,
A pic of the issue and the clutch master in the engine bay might help folks here to assess the issue.
Maybe your master cylinder is on its way out..
Clutch hydraulic fluid might have passed the pushrod piston seal in the cylinder and is now oozing out along the pushrod linkage.
On older clutch- and brake-cylinders, only the area the piston normally travels might be clean & smooth. Non-traveled areas might be rusty and pitted. When adjusting things or suddently using the full travel (e.g. when bleeding using the pedal method), the piston might get into the rusty area and rupture the seal.
Do you have a clutch booster ? (like a break booster, but on the clutch master cylinder; some J7s (like my BJ73) have that).
If so, what might be worse is that fluid might also fill the booster and, in combination with the vakkum actuation, might 'bubble'.
Suggest to peel back the boot and assess what comes out. How is your fluid level and pedal feeling?
There is a rare chance it was a one time event and cures itself after the fluid has leaked out, but I guess it'll rather become more serious over time, e.g after a longer or city ride with a lot of clutching & shifting. Monitor what unfolds, but I suggest to get a new master cylinder to be prepared.
Good Luck Ralf

 

[Touz]

Hi,
A pic of the issue and the clutch master in the engine bay might help folks here to assess the issue.
Maybe your master cylinder is on its way out..
Clutch hydraulic fluid might have passed the pushrod piston seal in the cylinder and is now oozing out along the pushrod linkage.
On older clutch- and brake-cylinders, only the area the piston normally travels might be clean & smooth. Non-traveled areas might be rusty and pitted. When adjusting things or suddently using the full travel (e.g. when bleeding using the pedal method), the piston might get into the rusty area and rupture the seal.
Do you have a clutch booster ? (like a break booster, but on the clutch master cylinder; some J7s (like my BJ73) have that).
If so, what might be worse is that fluid might also fill the booster and, in combination with the vakkum actuation, might 'bubble'.
Suggest to peel back the boot and assess what comes out. How is your fluid level and pedal feeling?
There is a rare chance it was a one time event and cures itself after the fluid has leaked out, but I guess it'll rather become more serious over time, e.g after a longer or city ride with a lot of clutching & shifting. Monitor what unfolds, but I suggest to get a new master cylinder to be prepared.
Good Luck Ralf

Thanks for the response Ralf. See photos attached. Photo of inside cab doesn't show much - just a glistening of the oil weeping through. If I poke my finger in there it is stained with dark brown oil. I do not have a clutch booster. The pedal is normal and the fluid level is not low.

On getting a new master cylinder, also just getting parts in general, is there an online retailer you can recommend? I have wandered whether there is a better way to go about ordering parts then just googling the name of the part and car model.... how does one go about getting actual Toyota part numbers? cheers

 

[Felde]

Hi
Sorry, the attached PDFs don't work, at least for me.
You are in AUS. I'm pretty sure there are local vendors for parts all over your continent, but as I'm in Europe, I can't help much on that.
There is a supporting vendors section here on Mud.
Terrain Tamer is a well known source in AUS for quality aftermarket and heavy duty parts, in particular well known for complete rebuild kits.

Many people go by parts distributors like amayama.com or partsouq.com. Both shipping from Japan and the Middle East. They both have detailed online parts catalogs you can enter by your VIN. The part catalogs are featuring explosion graphics, which are also a great source to generally understand how certain assemblies are designed and work.
Good Luck Ralf

 

[sodafeld1]

Sounds like brake fluid to me in that vicinity. It is common for one of the seals to go in the hydraulic system and brake fluid is caustic. Rubber perishes. Did you feel the leak and smell it?, certainly different to oil.

In melbourne for the most part, I get mostly toyota parts from amayama, shipping is by far the cheapest hands down, often building an order to $3-400, maybe $15 shipping. Amayama parts diagram is excellent. Often cheaper than the toyota dealer down the road themselves. But I do get the 12 pack of brake fluid from them most of the time. Engine oil when on sale 10l for 50-55 bucks from supercheap, repco or autobarn. Just stock up, 5k kms comes quick.

Locally, Terrain tamer for quality, sometimes they deliver directly themselves in their ute, they are in the nw part of melbourne. Their oil filters have been good to me. Sometimes ebay, online auto, road runner in warragul, tojo are good fellas but from queensland, etc depending on the part. There is a few lc parts dealers in oz.

I just replaced my clutch slave when i felt a bit of a slip and spotted a weep couple of weeks ago, have the terrain tamer master on the bench ready to replace that when i get round tuit. Probably lasted 4-5 years. No point mucking around if the slave or master is around that age, simply. I use a motive power bleeder for the hydraulics which imo is a far superior method.

You can get piston and seal kits for slave and master, but there is not much difference in price to a full new unit so often just get that.

Tricky to diagnose by sounds, old lc's are rattly things, part of the romance. Sounds like you are just getting familiar. How many k's on it?

Gosh after nearly 200k kms on my 2h 1988 troopy and I still play what's that sound or smell game. But yeah good to know or be fairly confident to have an educated guess. Always something to do on old cars. For example, I suspect a rear main or sump oil seal but live with a little dribble until I need to replace the clutch, as my oil loss is neglible, for a couple months now. Was so proud to have no weeps and dry underneath.

A brand new secondhand baseline is change all fluids like a bday party, then brakes and wheel bearings, hydraulics then driveline, steering, suspension..then..
$$$ the whole way, but you save on paying a mechanic and have greater affinity to the interalted mechanical universe which takes you places.

 

[Eurasiaoverland]

Brake fluid is not an oil and is in itself not caustic or corrosive. It will damage nitrile rubber over time, but the seals in the brake system are rubber (EPDM) so obviously are impervious to it.

The problem with brake fluid is that it is hygroscopic (absorbs moisture) and will over time, when mixed with water that has come rom the atmosphere or leaking seals/joints, rust out boosters and steel brake/clutch cylinders. That's why the fluid should be changed every couple of years.

Brake fluid contains glycol esters which will soften paint so you want to wash the leakng fluid off any painted surfaces pretty quickly.

Practically speaking, if the cylinder is leaking brake fluid, then chances are it's rusted internally and needs to be replaced. Change your brake fluid at the same time.

If you see signs of leakage, peeling paint and rust on the lower face of the brake booster below the master cylinder, you can be sure your master cylinder leaks, or has done in the past.

 

[Touz]

Sounds like brake fluid to me in that vicinity. It is common for one of the seals to go in the hydraulic system and brake fluid is caustic. Rubber perishes. Did you feel the leak and smell it?, certainly different to oil.

In melbourne for the most part, I get mostly toyota parts from amayama, shipping is by far the cheapest hands down, often building an order to $3-400, maybe $15 shipping. Amayama parts diagram is excellent. Often cheaper than the toyota dealer down the road themselves. But I do get the 12 pack of brake fluid from them most of the time. Engine oil when on sale 10l for 50-55 bucks from supercheap, repco or autobarn. Just stock up, 5k kms comes quick.

Locally, Terrain tamer for quality, sometimes they deliver directly themselves in their ute, they are in the nw part of melbourne. Their oil filters have been good to me. Sometimes ebay, online auto, road runner in warragul, tojo are good fellas but from queensland, etc depending on the part. There is a few lc parts dealers in oz.

I just replaced my clutch slave when i felt a bit of a slip and spotted a weep couple of weeks ago, have the terrain tamer master on the bench ready to replace that when i get round tuit. Probably lasted 4-5 years. No point mucking around if the slave or master is around that age, simply. I use a motive power bleeder for the hydraulics which imo is a far superior method.

You can get piston and seal kits for slave and master, but there is not much difference in price to a full new unit so often just get that.

Tricky to diagnose by sounds, old lc's are rattly things, part of the romance. Sounds like you are just getting familiar. How many k's on it?

Gosh after nearly 200k kms on my 2h 1988 troopy and I still play what's that sound or smell game. But yeah good to know or be fairly confident to have an educated guess. Always something to do on old cars. For example, I suspect a rear main or sump oil seal but live with a little dribble until I need to replace the clutch, as my oil loss is neglible, for a couple months now. Was so proud to have no weeps and dry underneath.

A brand new secondhand baseline is change all fluids like a bday party, then brakes and wheel bearings, hydraulics then driveline, steering, suspension..then..
$$$ the whole way, but you save on paying a mechanic and have greater affinity to the interalted mechanical universe which takes you places.

Thanks mate, amayama.com was just what I was looking for. I reckon I'll just get a full cylinder kit and keep ready for install when the other one goes. I'll sleep easier that way. My troopy is up to 430km, bought it at 425km with the engine rebuilt.

 

[Touz]

Hi
Sorry, the attached PDFs don't work, at least for me.
You are in AUS. I'm pretty sure there are local vendors for parts all over your continent, but as I'm in Europe, I can't help much on that.
There is a supporting vendors section here on Mud.
Terrain Tamer is a well known source in AUS for quality aftermarket and heavy duty parts, in particular well known for complete rebuild kits.

Many people go by parts distributors like amayama.com or partsouq.com. Both shipping from Japan and the Middle East. They both have detailed online parts catalogs you can enter by your VIN. The part catalogs are featuring explosion graphics, which are also a great source to generally understand how certain assemblies are designed and work.
Good Luck Ralf

Thanks for the help

 

[Felde]

Don't wait too long. Get the part in as soon as possible.
Apparently, you are still busy baselineing the truck. If the master turns out to be rusted, the slave might be no better.
And if the clutch has this issue, the brakes might have, too.
As also suggested by the others: If not yet done, it's ime to replace all hydraulic fluids (also in the lines) and at least start a close monitoring of all cylinders. Have a plan for replacements at hand and probably the parts on the shelf.
Good Luck Ralf

 

[sodafeld1]

Brake fluid is not an oil and is in itself not caustic or corrosive. It will damage nitrile rubber over time, but the seals in the brake system are rubber (EPDM) so obviously are impervious to it.

The problem with brake fluid is that it is hygroscopic (absorbs moisture) and will over time, when mixed with water that has come rom the atmosphere or leaking seals/joints, rust out boosters and steel brake/clutch cylinders. That's why the fluid should be changed every couple of years.

Brake fluid contains glycol esters which will soften paint so you want to wash the leakng fluid off any painted surfaces pretty quickly.

Practically speaking, if the cylinder is leaking brake fluid, then chances are it's rusted internally and needs to be replaced. Change your brake fluid at the same time.

If you see signs of leakage, peeling paint and rust on the lower face of the brake booster below the master cylinder, you can be sure your master cylinder leaks, or has done in the past.

I guess that's why the brake fluid appears as corrosive, by softening the paint extremely quickly and in turn inviting rust. Explains why I can use it as excellent paint stripper. But coolant does not seem to work as effectively, could test it out as a project.

But my weeping slave was getting flushed fairly frequently, so to be more concise if I do lots of start stop driving the rubber seals would wear I guess. Honestly never looked into which type of rubber was used in the seals, but yes makes sense nitrile is good for somethings epdm is better for others. Also the quality of the manufacturer.

Also strikes me as a scam when they try selling seal refresher snake oil for engines which leak, how can it soften silicone without breaking it down for example? There is quite a few rubbers.

And I think my slipping clutch is a progressive thing and changing the slave has just given a little more time for the bigger job.
I have noticed a few posts on 70's that the clutch hydraulics seem to get dirty pretty quick., not just me in my back yard.

wow you know your stuff euroasia! set my bumpkin straighter , thank you. learning

 

[Touz]

Don't wait too long. Get the part in as soon as possible.
Apparently, you are still busy baselineing the truck. If the master turns out to be rusted, the slave might be no better.
And if the clutch has this issue, the brakes might have, too.
As also suggested by the others: If not yet done, it's ime to replace all hydraulic fluids (also in the lines) and at least start a close monitoring of all cylinders. Have a plan for replacements at hand and probably the parts on the shelf.
Good Luck Ralf

I like the way you put that: baseline. Yes, I'm in the process of getting the baseline. I appreciate the help.
When you say "all cylinders", do mean master/slave for clutch and master/slave for brakes? Any others to think about, or tips on other spare parts to have on the shelf? I'm getting the hang of all the fluids and filters to keep an eye on and have spare. Next I need to look at the drive belt tensions as I'm getting a lot of squeaking when it's cold in the morning and night. After that I need to get my head around the electrics, a slight coolant leak... it's endless!

 

[Felde]

Hi
For baselining, I'd condider:
- Engine belts, in particular timing belt, if present.
- Engine coolant change and thermostat check / clean.
- Air filter.
- Check hoses for brittle (fuel, coolant, vakuum) and leaks, also check the hardlines and connecting pieces of rubber hose. *
- Replace fuel filter (P), check sedimenter,
- All oils change (Engine, gearbox, transfer case, front & rear diff). (P)
- Check axle and gearbox breathers for proper function.
- All hydraulic fluids change (clutch, brake) and powersteering fluid, also in the lines.
- Service brakes (rotors, pads, drums, shoes), bleed and adjust. This includes: Check brake booster to be seal, check / adjust load sentencing proportional valve (LSPV), Check master- and slave-cylinders for leaks. *
- Check wheel bearings abd kuckles for play.
Replacing wheel bearings is usually only done as needed (P), as well as 'the knuckle job' to fix leaking oil/greas from the knuckle spheres and replacing bearings (P).
- Check steering gear and tierod ends for wear and play (P).
- Check bushings on springs and swaybars (frequent cause for 'Death wobble').
- Grease everything that needs to be greased.
- Check electrical system (look behind the dash and panels, expect some fancy installations b previous owners to be cleaned up). Check for correct fusing.
- Check and adjust lights.

I'm sure I forgot something. The community will add it
* indicates regular monitoring
(P) indicates parts on the shelf.

For the shelf, I suggest to get a bulk of oils as needed, fuel filter, oil filter, belts, brake pads.
Plus all service items you didn't immediately replace, e.g. brake shoes, set of tierod ends, kit for knuckle job + wheel bearings ...
It also depends a bit on how fast you can get in parts, if needed.
Good Luck Ralf

 

[Touz]

Hi
For baselining, I'd condider:
- Engine belts, in particular timing belt, if present.
- Engine coolant change and thermostat check / clean.
- Air filter.
- Check hoses for brittle (fuel, coolant, vakuum) and leaks, also check the hardlines and connecting pieces of rubber hose. *
- Replace fuel filter (P), check sedimenter,
- All oils change (Engine, gearbox, transfer case, front & rear diff). (P)
- Check axle and gearbox breathers for proper function.
- All hydraulic fluids change (clutch, brake) and powersteering fluid, also in the lines.
- Service brakes (rotors, pads, drums, shoes), bleed and adjust. This includes: Check brake booster to be seal, check / adjust load sentencing proportional valve (LSPV), Check master- and slave-cylinders for leaks. *
- Check wheel bearings abd kuckles for play.
Replacing wheel bearings is usually only done as needed (P), as well as 'the knuckle job' to fix leaking oil/greas from the knuckle spheres and replacing bearings (P).
- Check steering gear and tierod ends for wear and play (P).
- Check bushings on springs and swaybars (frequent cause for 'Death wobble').
- Grease everything that needs to be greased.
- Check electrical system (look behind the dash and panels, expect some fancy installations b previous owners to be cleaned up). Check for correct fusing.
- Check and adjust lights.

I'm sure I forgot something. The community will add it
* indicates regular monitoring
(P) indicates parts on the shelf.

For the shelf, I suggest to get a bulk of oils as needed, fuel filter, oil filter, belts, brake pads.
Plus all service items you didn't immediately replace, e.g. brake shoes, set of tierod ends, kit for knuckle job + wheel bearings ...
It also depends a bit on how fast you can get in parts, if needed.
Good Luck Ralf

Thanks Ralf, added all that to my maintenance spreadsheet