Lj71 braking

[gsebas]

Hi everyone,

I experience poor braking capacity with my 1987 lj71 truck. It’s not a big problem since the truck is not really fast as you know but I have been pulling a small camper and I don’t feel safe enough in these conditions… it is equipped with standard disc in front and drums at the back. What are my options ? Should I replace the drums with discs , the master cylinder or both ? Should I install ventilated discs in front ? Anyone fixed that issue?

Thanks in advance !

 

[AirheadNut]

What are the symptoms? Poor pedal feel, or simply not good enough stopping power? Start with the basics: check front pad and rear shoe wear, make sure drums are adjusted properly, and fully bleed the hydraulic system with fresh fluid. A couple of years ago I rescued a 1975 Mercedes from a field where it had been sitting for at least a decade; when I got it running the brakes were quite poor but after bleeding the system they improved dramatically and were on par with cars 30 years newer.

 

[Felde]

Hi
I second @AirheadNut : Suggest to start with a thorough brake service and a brake force check on a meter.
You have the short wheelbase and your issue is while pulling a trailer, so it's probably not an issue on the LSPV (as the back won't lift much when braking under these conditions), provided the truck brakes good without the trailer. Check the LSPV anyways (I guess it has one). Wouldn't be the first rig with poor braking in the back due to a stuck / clogged LSPV.
Check / changed your brake-pads / -shoes: Glassed brakelinings reduce braking power (not to speak of being oily)
Also check / meter your vakuum system, to make sure your brake booster can properly do its job.
The FSM has the procedure to check the booster for internal leaks.
If the brakes are all OK, but still not good enough for you, and pulling a trailer is common use case, you might consider upgrading your brakes.
There are heavy duty brake kits available (e.g. from Terrain Tamer), but those basically improve heat capacity/ avoid fading and are more longlasting.
To increase power, you would need to increase the force, e.g by a bigger booster. The J80s booster works, with some mods.
There are threats on mud on this (including a lot of debate on what really increases braking power and avoids wear, heat & fading).
Good Luck Ralf

 

[gsebas]

The braking power is weak even when i am not pulling… feeling on the brake pedal is fine and i don’t think it’s related to overheating since the performance never changes from the first brake to the last… Thank you guys for your generosity! will look into that before considering replacing the old system.